Desperate for help with Retro Active jealousy

Hi guys, I'm new here. Don't quite know what I'm doing but desperately looking for an answer with this retroactive jealousy I am dealing with. I love my boyfriend, we've known each other for almost three years and he met my mom right before she passed away. He's the love of my life but I obsess over his past. I can't get the images out of my head, I can't stop obsessing. It's all day long, all the time...sends me in to anxiety attacks and leaves me feeling exhausted with fog brain...I'm even losing my hair and appetite. Someone please help me this is such a burden and I can't take it anymore :( I love him so much and my heart can't accept that I'm not his first, and the crazy party days of his past (I wish he never gave me detail) is haunting me. Images, self doubt, anxiety, fear....those are the things I feel from the moment I wake up until I fall asleep. If anyone could give me some advice, I would greatly appreciate it. I feel hopeless and like I've tried everything