I don’t want to go to the wedding

Can't you just go to the church/registrar office bit? Explain to your friend that you would love to see the young couple actually wed, but you really don't like big dos. Give them a really nice present. That will make up for a lot.

Could you attend the church service but not the reception?
At least in the church it will be calm and with an order of service. A wave or quick hello to those you know and take your seat. You can slip away quietly while photographs are being taken.

Of course your not being unreasonable. It is up to you whether you go or not. I completely understand how you feel and I wouldn’t go in the circumstances either. Unfortunately your friend may be a bit upset at your stance, but if she’s a real friend she will understand when you explain how you feel.

Sort it quickly - give your friend time to invite someone else in your place

Yes Mande, I can empathise with you. I too am not fond of big weddings or parties etc , but for a different reason. I am divorced and my ex-husband and his wife are usually invited as well ....it's always awkward for me and no one understands.
In your case, you have a very valid and distressing reason (your medical condition) ... if she's a good friend she will understand. You can visit the couple, when convenient and wish them well, personally . Good luck xx

I felt the same a few years ago when invited to my Friends golden Wedding celebration.
It was a very big affair, marquee, cateres etc.
My H had Alzheimer's and I didnt want to go on my own, too many memories and too many acquaintances.
I explained to my friends and they "sort of" understood.
I sent a generous checque to a charity of their choice and my friend took me out for lunch a couple of weeks later.
Now, at my age, I will not do anything I don't want to or know I will be uncomfortable ,trying not to hurt feelings though.

Thank you all for your replies. They are very reassuring. I’m not sure yet about going to the church as i know I’ll have to continually explain to others why I’m not going. Maybe too stressful.
It’s good to know I’m not alone in my way of thinking. 🙂

I had the same experience recently about a friend’s wedding and was agonising about my response. Two friends from this forum advised me that it was ok to turn down the invitation. I explained to my friend why I found it socially very difficult to attend and she was fine. So Mande do what your heart tells you to do.

Just be honest with her- and don't fall out because of it.
Explain you feel very uncomfortable in crowds, and that you panic, etc. If she doesn't understand, then a pity.

I have been in a similar situation several times - first of all because I was the last in my circle of friends to get married (and always seemed to be in between relationships at the time) and when I was divorced, I was the gooseberry and seen by some females as looking to grab their husband/ partner !
So I stopped going to weddings, christenings and stuff and even though I explained that I felt uncomfortable going on my own, I lost several, who I thought, good friends as a consequence of not going to join in their big day.
I think you should just explain to your friend that you feel so uncomfortable on your own and you would love to go to the ceremony but not the reception and maybe have a girly lunch with the bride and your friend either before or after the wedding ?
If all else fails, a sudden attack of "tummy bug" on the day !

You shouldn’t do anything you don’t want to do. If she’s a good friend she’ll understand

Yes Sara65 is right, don't go if you are not comfortable with it.

If you do decide to go to the ceremony, you have no need to explain to anyone there your reasons for not attending the reception. As has been said you can slip away during the photos. Or if someone says about the reception you could say you wanted to see them wed but sadly had a prior engagement for later that day.
If she is a good friend, she will understand. I think the idea of a girly lunch with the bride and her mum is a great suggestion.

It’s kind that they’ve invited you, but trust me, they’ll have a lot more to think about than your not wishing to attend! Just tell the truth, I’m certain they’ll be fine with it

There are very few things in life you have to do, and going to a wedding reception is not one of them. Go to the church, if you wan to, then just go home.if you decide to do this, tell your friend so she can invite someone else to the reception, but just say you are delighted to have been invited and are looking forward to the ceremony, but will not go to the reception. No need to make up any excuses.

I am sure your friend will understand, particularly bearing in mind your recent diagnosis, go with what you want to do. If you have known the bride since she was a small child it might be nice to go to the church if you feel you can.

Must say I'd much prefer a friend to be honest- than pull a 'tummy bug' on the day- meaning too that the dinner would have to be paid for, and it is not cheap.

Thank you everyone for your thoughts and kindness. I have spoken to my friend and she understands. I will be meeting up with her and the bride along with our other friends before the big day. So all is good!

Can you take a plus one? It doesn't have to be a man/partner

You've done the best thing mande. True friends understand, hope you have a lovely meet up.