Breastfeeding

My son is 3 months old. I breast feed him and occasionally he takes a bottle of expressed milk. He usually vomits most of the bottle and is never settled from it. He breast feeds every hour to every 3 (rarely) through the day. He has one 5 hour block at night and then wakes every hour. I've tried spreading his feeds out but he just screams. Breastfeeding is very painful for me. I've seen specialists, midwives, lactation consultants and they don't know what's why. I hate breastfeeding. I wanted to do it so badly but now every feed is so stressful and upsetting. I even stress about having a shower because I know he will only be calm if I'm holding him while he sleeps or feeding him. He fights sleep all day and all night. I don't want to breast feed anymore but I feel so guilty and he hates bottles so much that I don't know how I'll ever settle him. I'm exhausted and feel shitty and guilty enough so please don't be harsh. I feel so bad for my toddler. He never gets the attention he needs because I'm always attached to my youngest son. I always want to give my sons what's best for them but I'm so torn between them and how I feel and the stress it's putting on my marriage. So how do I stop breast feeding my son who hates bottles and is already so unsettled.