Guilty about wanting to stop bf

I have been having terrible pp anxiety. I went on zoloft then stopped it bc it was making things worse. Then started having an elevated heart rate to where I was in the ER twice this weekend and now I'm on metoprolol. I know breastfeeding causes hormones that can trigger anxiety and it's getting more cumbersome to pump at work. I co sleep because all my son wants to do is nurse at night and I only hold my son all night after work because he wants to nurse. I have no life anymore. But the thought of going from breastmilk to formula is upsetting me because I had planned to do this for a year and I hate quitting on my goals. He loves nursing so I feel guilty taking that away from him.