A lifestyle audit is what is required here (as well as possible a look at the non hormonal coil) as it is most likely that your hormones are not to blame but rather - as you said yourself - your current situation.
In a nut shell, you need to make some changes with the things that you can alter; for example, being more organised in making sure that you are eating a good healthy balanced diet, and making sure that you are consuming at least a litre and a half of water per day, whether you go home or to your boyfriends.
Do make time for exercise - even if it just for 10 mins a day! Make sure that you are getting plenty of sleep (look at Deep Sleep if you feel you need a hand to get a good nights (days) sleep) .
You would also benefit from using a good magnesium supplement along with a B vitamin supplement too, these products will greatly help with your stress levels which should, in turn, help turn around the way your body is feeling before your period and hopefully banish the majority of symptoms.
Keep track of your symptoms with our PMS Diary to identify patterns & help discover ways to minimise them.
Try to do this for a couple of months and should you have any further questions please let me know; and do let me know how you get on as I'd like to know.