If, when it was first taken and was up, you then subconsciously panicked every time afterwards, then this could have it going up and down. It's a begger because we can't see it. And I do think keep taking it makes it worse too, especially at home where you feel normally safe and secure.
I had pre-eclampsia with my daughter and was in hospital for 12 weeks prior to her birth so became paranoid about blood pressure readings. I was allowed home for the weekend if it was below 100 diastolic. I have been paranoid since and especially when having my son. I used to imagine him inside, holding onto the blood vessels and making it go down. Now, when the cuff is put on, I say in my mind in a low, deep voice - down, down, down. It seems to help me stay calm and my readings recently have been 84, which is good for me.
Do you have someone at home with you who could help you take a reading or a neighbour who could hold your hand? Just some comfort might make a difference. It's amazing how worked up we get without even knowing it. Maybe look at minerals which might help to bring it down a little. We know little about these important elements and just tweaking can make a difference. I take magnesium and it helps tremendously for various things. Be pro active about this, do some research and try to help yourself. Modern medication is great but personally I like to find out why something is happening in my body and try to rectify the cause, not just treat the symptoms.
Good luck, I hope it soon settles down. 