I'm rooting for you.
The suicidal feelings are the worst, and the psychotherapists are doing an awful job at being empathetic towards people with our condition because we're "tough to work with".
Do get into journaling, write down your feelings, track your mood swings, and everything else; thoughts, people you come into contact with, times you eat, and so on. You'll eventually find triggers and establish connections. You need to see the warning signs.
It's true that some states can be aggravated by changes in weather or an imbalance in diet (make sure your vitamins and minerals are in-check).
The boyfriend deal, I'm not gonna lie, don't take it to heart. Always ask yourself whether you want to commit or not, and if you see yourself with this person in the years to come. If your answer is negative, then don't waste your energy, you've got enough to work on already.
Let me know how you're feeling and I'm here if you need anyone to chat with. Just hit me up with a DM.