pms and suicidal thoughts

Okay, so I have always had problems with severe anxiety and depression, and I can generally deal with it, but I've noticed that whenever Im about to start my period/whenever I get to a certain point in my hormonal cycle (I do not have anything close to *regular* periods but I still have a clear cycle) the depression goes up about 10000% and i go from depressed to deeply suicidal/self destructive, to the point where I start self harming and planning out final notes. 
I kinda just wanna know if anyone else deals with this every month, and if there's any way to avoid it or make it less severe? At the moment I'm on my summer break and staying with my very supportive boyfriend so it's much easier to deal with, but this fall I'm moving back into my college dorm where I don't really know anyone, and the stress might end up pushing me too far this time!
((Also: I feel real bad talking about it because I'm really afraid people aren't going to take my depression seriously, like they'll think "oh you're just pms-ing you're fine!", as if my suicide is gonna be less real just because I'm on my period lol))