Getting healthy questions

Anyone who has been on a health/weight loss journey. Please help!!

I’ve lost 50 lbs. I’ve had 2 C-sections 11 & 4 years ago. Now that I’m fairly thinner and have been starting some ab workouts to tone, I’ve noticed that I can feel every little sensation in my abdominal area. The fold of skin hanging over my C-section scar is really uncomfortable when I sit, like I feel it putting pressure on my lower abdomen. I’m always feeling weird after I eat anymore, like my stomach is pushing on something.

For reference, I’ve never had a strong core. In fact it was my body’s weakest link. Is this because I now have abs? Or could something weird be going on? Do I just have to adjust to not being round and fluffy anymore? I feel nauseous as soon as I finish my ab workouts too. Is that normal?