Hi there,
By not making a decision, you are making a decision. You still have time but I think as the weeks go on the certainty for a termination needs to be even more absolute.
I had a very difficult third pregnancy. I went into denial for a long time and just didn't discuss it. I made multiple appointments for a termination (up to about 16 weeks) and never attended them, and I sobbed through my booking in appointment with my midwife. I catastrophised every possible outcome. However, having had an abortion in the past and really struggled afterwards, I just couldn't do it again.
Many people do walk away from abortions with relief and no regrets. It's a weird one that it can be hard to tell how you'll feel overall until a few months afterwards. I just knew for me it had been really hard and I was scared at feeling that way again.
It did get easier as the weeks went on. Telling people helped - seeing them be happy for me. I took antidepressants until around 20 weeks and then stopped and coped. After he was born (planned C-section due to previous traumatic birth), it was easier too than being pregnant. I was worried about postnatal depression but luckily it didn't happen. He was generally a content baby, his siblings adore him and he's probably the most like his dad of the three and is therefore the apple of his eye.
It's a bit harder now he's a toddler. Just because he's a very high energy toddler boy. Occasionally I wistfully think how easy my life would be with just the two (I don't admit this to anyone) but overall I think I would have definitely have struggled more with having an abortion and seeing families with 3 children etc. But that's just me. I suppose I'd never ruled out having three children in the past, and I didn't overly struggle with having two of them previously. I don't know you or your situation, but all I can say is that nothing was as bad as I made it in my head.