Looking to Get my Old Body Back

It's been 3weeks now I started working out slowly at 30 min doing 1.5 miles and now I'm up to 40 min 2 mile I tried some abs today but bad idea I was in pain for about 3hrs I got a smaller garment today went from xl to l because I felt thr xl wasn't really compressing I feel like it makes my but look or maybe its just bigger lol

I hope I'm not doing too much I think I took not too slow but today I did 1.5 miles in 30 min total burn of calories was 200 I want to speed up but I'm scared to do wrong how do you know when its too much?

I'm just so amazed and in love with my new body and I know its going to get better :D