21 weeks and trying to exercise.... having really bad back pain, advice?

Ladybug

I’m 21 weeks & trying to exercise... at least walk on my treadmill where I’ll go 1-1.5 mi at a steady/slower pace but it KILLS my lower back afterwards... it’s been 2 days and nothing is working to alleviate the pain.

I’ve tried stretching, using a foam roller, yoga poses, exercise ball and even walking again bc I read that can help and nada!

I don’t want to just sit around getting extra fat while preggers... I have the energy to workout but the back pain afterwards is horrible.

Also: I’d love to go swimming and know thats better but I have to work and community pool hours are not compatible with any kind of regular schedule.

Any advice, stretches, etc are appreciated. Also it’s my lower right back above my glutes mainly.