Re lactating

Hey mums,
I have a 15 week old baby boy. He was tounge tied when he was born so breastfeeding was hard and painful. He wasn't able to latch and the doctors at the hospital took a while to snip the tie. However I expressed my milk and gave him EBM for 4 weeks. During that time I got mastitis and ended up in hospital for over a week treating it. While in hospital I didn't get the support I needed. I was in a lot of pain, trying to breastfeed and expressing after every feed during the night (it felt like I had twins!). During the stay in hospital his tounge was snipped but by then he was used to the bottle and refused to latch. When I got home the mastitis kept coming back so I gave up breastfeeding and slowly weened myself with the breastpump.
He is now formula fed and has been since 4 weeks old. I riddled with guilt that I didn't try harder and angry that I didn't get the support that I needed when I was exhausted in hospital. I am desperate to try to re lactate. I was wondering if any mums out there have had success in doing this and ways to go around it. Any advice would be highly appreciated.
Thank you
Xxx :)