How to deal with menstrual cycle in the Navy?

So it might sound like a stupid question but here are the details. I have horrible periods. My mom wants me to see a OBGYN. What i get is what she has now and she is currently going to get a hysterectomy for cystic fibrosis stuff. So who knows if it could run in the family. Her sister had the same and also had a hysterectomy. I'm 20 by the way. My periods have always been really bad, to the point where I had to call my mom to pick me up from school or now that i am older I have to call off work for 3 days. I cry myself to sleep at night from the horrible back cramps that i get. The first day of the cycle I get really sweaty, and faint like, i even go pale for a couple of hours. Then after i throw up or use the toilet, I stop with the fever chills and sweat and just get really bad cramps. I noticed the I get super bad cramps cause i get chunks of blood. Is that normal? To get chunks of blood during your period? My mom has to give me one of her 800 mg ibuprofen pills so that i won't have to scarf down 4 Tylenol pills. Now, I am joining the Navy, and i know its no walk in the park. How the heck do I deal with this type of period that i get while i am in the navy. i want to do aircrew and that deals with a lot of swimming. I can't just call up my superior and say, "Hey i'm having super bad cramps, I can't go to work or PT." Like hell it will be that easy to do. I've tried Birth control Pills to control the symptoms. I've tried several kinds, one that really worked was Yasmin but thats bad now. Whatever else I've taken doesn't really work now. I was thinking an IUD, but i heard I should wait till I'm at my first station.