This sounds like a very stressful time for you, I'm sorry. I haven't had migraines, but I used to get severe anxiety from a medication I used to take. It would come out of no where, I hated it!

Do you exercise on a daily basis? I know with a busy life it can seem hard to make time. But if you do, exercise reduces stress and makes you feel more energetic. Not only that, it usually helps with migraines! If you hate going to the gym, maybe pick up a fun sport you can do with the bf or a girlfriend you might have. Even just taking a brisk 20 minute walk a day can make a difference. Pilates and yoga are great for stress relief.

I HATE going to the gym and working out in general. My bf and I started playing tennis together. Its SO much fun. Its made me feel less stressed, more energetic, and has brought some fun into our relationship.
Talk with your bf about things that are bothering you (You probably already have). Make a plan about how you guys can change your relationship into something more positive. Do something fun together; sign up for classes to learn a language you've wanted to learn, maybe some volunteer work you're both interested in, etc.

I know how easy it can be for people to say "let him go", when they may not know the whole story. It's for you to decide whether you think you can change your relationship, or whether it won't be healthy in the long run. Just make sure whatever you decide will make YOU happy down the road.