Good morning love! Sorry to hear about the bed, stress does manifest in many ways, this is so early in all of this, it does get better.
Now, to you.
Doubling up on AD meds probably won't help on any front. Most meds take weeks to activate/come into effect, and depending on what ad it is, can increase side effects or be harmful.
As wretched as you feel, try to remind yourself that this event really is awful, and it's utterly to be expected that you will feel awful. I understand why you did this, but you can't medicate this situation away, and nor should you try. From the feelings and thoughts you have you will grow. You will struggle to see this now perhaps, but you will.
If at any time you feel depression spiralling, please either call the Samaritans or come onto Mumsnet for some hand holding.
Your mother's support was bloody awful, i'm so sorry to hear this, but please don't turn to her again, please call your friends and see who will help you feel better. Please use mumsnet if you find it helpful.
Can you take the boys out, or if you drop them at soft play, could someone bring them back afterwards? Do you have a mum-friend that's going that you could confide in?
In terms of what's next, I think if you can aim to keep everything as normal as possible, but only do what you realistically can do.
If I were you, i'd do the nursery/school run, go into work and ask to see my manager. I'd explain the situation and ask for the day off while I gathered my thoughts alone for a day.
I've said this before, but will say it again: you really will get through this lovey!