How to increase milk supply?

Hello mamas!

I am desperate for help. I have hypothyroidism and I cant afford the visit to a primary care doctor so I’m currently not on meds for it or anything. As a result my milk supply is nowhere close to where it should be. My son can’t take formula as they all mess with his tummy too much. I am losing a lot of sleep because I have to pump him a new bottle right after he eats. And some times he eats that before he goes back to bed because of how little I pump and then I lose more sleep waiting until I can try and get more milk out before he wakes back up. Everything I’ve tried hasn’t helped. Letting my breasts sit under hot water helps the most but I still only get about a bottle and a half. Did any of you have a similar issue? What helped you? I also always have my son on me skin to skin, and I am constantly kissing and smelling him. So even though those help most it isn’t doing much for me.