Am I over-reacting because my apology seems to have fallen on deaf ears

I agree with Calendargirl's comments, it is likely that your apology has been accepted, most will think that you have nothing to apologise for anyway, and they may think that by acknowledging your apology they are confirming that the apology was needed. Please attend the next zoom meeting, all will be forgotten.

As a group you’ve shared vulnerabilities and they know you well enough to appreciate you’re anxious from time to time, that your son’s situation will have exacerbated your worries.
Your friend and husband have given you excellent advice.
The group won’t be as concerned about this as you are, probably aren’t giving it a second thought. That’s what you need to do. Yes, they do care otherwise your friend wouldn’t have tactfully and discretely spoken to you. The lack of response to your apology suggests they don’t see it as a big issue which embarrasses you. You’re not being avoided or ignored: you’ve been invited next time when you could have been left out.
Don’t leave the group. See them at the next meeting, be cheerful and smile throughout. You’ll be fine.

Perhaps the others in the group feel it’s a case of “Least said, soonest mended”.

I can imagine you feel awkward, but if I were you, I would go to the next meeting, but keep reminding myself to keep a low profile.

I’m sure the rest of the group are sympathetic to your anxieties, but feel it’s best if the just don’t pass any comment and maybe upset you more.

The last group lunch I went one of the older ladies did this. She went on for over 20 minutes about conversations her daughter had with someone we don't know. It was all 'she got dressed and went to the house, I told her not to go, She didn't listen, my husband said....etc'Really boring and we couldn't get a word in.
However, everyone likes her and no one wants to exclude her next time.

Thanks to those who have replied so far. icanhandthemback - the truth is that there are plenty of people like us who enjoy telling stories and anecdotes but I probably hogged the conversation a bit too much that day.

It's not a hanging offence and I am grateful to have had it pointed out to me. I just feel really embarrassed about it. It must be something I do when I'm stressed or anxious.

Apart from apologising and trying not to repeat the behaviour I am not sure what else I can do.

Yes, you are over reacting

I see several issues here:
1. Why apologize to the whole group? This may have been seen as oversharing and more examples of the chatty behavior
It could also be seen as attention seeking as well
2. If you apologize expecting support and sympathy from the group, it may have been a reason why they do not reply
What is the purpose of the group?
Please look for support anywhere else instead of putting that role on them
3. Maybe only one person was annoyed at your chatting and everybody else was fine - is that a possibility?
4. Please don't leave the group. Learn from the experience and give short answers, do some people watching.

Ramblingrose22, I do this too and the more I search to make sure the people I am addressing aren't yawning from boredom, the more I witter on. Half the time I really don't recognise social cues in conversation. Afterwards, I go through things I have wittered on about and cringe. My husband says I must stop worrying and not bother about what other people think but it is difficult.

My advice to you would be to just go back the group and enjoy the bits you can. At least you know that there is someone who will gently indicate that you are overdoing the chatter so perhaps take that as a positive rather than a negative.

I hope your son is feeling better and you can relax a bit.

What were you talking about?

I don't see any reason for not answering someone for being too chatty

You wouldn't owe an apology for that, maybe they just don't know how to respond or are worried they made you feel like you needed to apologise

I think just go to the next meeting as usual and if nothing is said by anyone just try to forget it. I’m sure it wasn’t as bad as you think and although no one has got in touch they’re probably all sorry about your son. Maybe they’re all busy with Christmas stuff. Try not to worry.

They may not want to embarrass you - just go to the meeting and act as you usually do.
We all have moments like this - just don't dwell on it too much!