Am I in the wrong?

I currently have an almost 1 year old (Feb 7th is his bday) son who I breast fed for the past 11 months. I found out I was pregnant and decided that I wanted to stop breastfeeding as it was causing so much pain to the point where I was crying. Not only that, my son was barely getting anything. We’d be up for hours at night just switching sides to fill his tummy. I also wanted a break before baby #2 gets here so that way my body could rest and bring it’s supply back up. So I stopped and switched to formula. We’ve been going really good for the past (almost) 2 weeks now but my son is sick and very upset. My S/O is constantly getting upset with me and telling me that I need to breastfeed while he’s sick because my body can help him get better faster. And I understand this and it sucks but I’m really trying to stay strong because my son is doing so well with the switch. I already feel like a bad mom and having his constant nag doesn’t help. I just want some support and he says that he does but when he gets mad and snaps on me and tells me that I just need to suck it up and do it really hurts.

Am I wrong for not breast feeding my son while he’s sick? Am I wrong and selfish for wanting to stop?

Edited to add that my son absolutely LOVES the bottle. He knows what it means and gets so excited every time I start making a bottle