Not losing it

I'm sure you get this post alot but I'm struggling, so any insight would help.

I had a baby 2 years ago. Gained a healthy 35 pounds in pregnancy and then lost 20 lbs within the first 3 months. The last 15 lbs have not budged. I went from 135 before pregnancy to 150 at 3 months post partum, and have stayed there for the last 2 years. I am 5 feet tall.

I am no stranger to counting calories and exercising. I have always struggled with my weight and did well keeping my calories down around 1200-1300 before getting pregnant to lose weight and maintain around 130-135. I know how to count correctly, I know to count my sauces, I go light on the oil. I count by weight not by cups so it's more accurate, etc.

Post pregnancy ive noticed that 1200 doesn't cut it some times. I am significantly more active now than I was before the baby. I am constantly running around after my 2 year old. In good weather we go on atleast a 1 mile walk 4 days a week, but usually it's 2 miles. That's on top of just running after him in the house, and being a teacher at work (constantly moving and on my feet). Unfortunately I don't have much time to get to a gym or do extensive workouts. I upped my calories to 1450 some days, though some I am fine with the 1200. It makes sense though that I would need the extra 250 with how much more active I am.

That all being said, I am not losing any weight! I cannot drop below 150 and have been trying and consistent for atleast a year (probably more like a year and a half but the first year of a baby is rough). On vacation, when I'm not being strict, I might go up to 158 or 160, and I will lose that again within the next two weeks of eating normally again, but once I hit that 150 it won't go lower. Ive had my thyroid checked, I've had blood tested, and everything comes back normal. I am just so defeated because I am doing everything the same as I did before pregnancy where I could pretty easily lose and maintain weight but now it's doing nothing.

I have a pretty prominent apron belly (also had a c section which doesn't help that) that I am so self conscious with now. I really just want to lose that extra 10 to 15 lbs to get to what I was pre pregnancy. Does anyone have any insights on what I might be missing?