My son was very similar. We actually had to resort to using a thickener in his bottles and it was like night and day, no more spitting up! Simply Thick and Thick It are 2 brands. They are available at most drugstores and I think are used for diabetics or something, not sure. We used simply thick packets. (Looked like ketchup packets.) Added it to his bottle and stirred. It was magical. And totally safe for a little one because it honestly has nothing in it, its not a medicine.
I was never able to successfully breastfeed with either of my kids. I saw several lactation consultants and tried it all, even medication. I just never produced enough. I remember the heartbreak of feeding my babies and then hearing them cry and having nothing for them, I feel for you. You do what you have to do, and sometimes it isnt your 1st choice but formula exists for a reason. I would have less than 2 oz collected at the end of a day of pumping every 2 hrs. It was horrible.