Hi OP, name changed to answer this as I can relate, it's an absolutely awful time.
I had a termination 18 months ago, when my 2 DC were both under 5. I went round in circles too, mainly because although there were loads of good reasons not to proceed, they were probably manageable enough, and we could have muddled through ok.
Ultimately I went ahead with the procedure as I realized it was mainly the terrible guilt that was throwing me off so badly. Of course in a perfect world I'd like to have gone ahead, I'd never NOT want any baby of mine - that's why it's such an awful dilemma. But the circumstances were definitely not right and on balance I felt it in all our interests not to have it. My first sinking gut feel never went away, so I went with it.
I cried a lot of tears and on the day of the pills I sobbed at what an awful person I was. I think it probably goes against all our natural instincts. But I didn't really doubt the choice I'd made was the right one. I actually felt much better for having made a decision. The limbo was truly the worst part.
The process was painless and over quickly, and I can honestly say I've never regretted it, nor dwelled on it. I think the underlying guilt will always be there, and I'll have the odd random pang when I'm in the shower, or watching something on tv. But there has been nothing strong enough to overpower the relief, or make me unhappy. I believe a decision can be dreadful, but still be right.
Sorry that's a bit of a ramble. It's very hard to give advice as the decision is SO personal, and nobody takes it lightly. It's trite but I think whatever you go with IS the right choice. Good luck to you, it will work out. X