I have just answered your other question about career. Somehow I wanted you to check if you are mixing your career related issues with your personal life. Just recall the recent series of incidents and try to figure out if you are showing your anxiety caused by studies in your relationship. Let me tell you, boys have the tendency to bear anger or complaints to a limit. Once the limits crosses, they tend to behave opposite, which may in turn makes girls negative. So, though the suggestions like yoga, meditation and all are there, it's ultimately your thought process that you need to work on.....Some points that I would do if I were in your place, check if these points work for you
1. While in discussion and before you react or reply to your bf, count 10 numbers and give time to yourself to think and give the reply. It's even better to stay silent without any reply and tell him that you will speak later than saying out something. So, do take some time before you reply. Think on what to reply or how to restrict
2. When you are not in angry state or in good mood, give him a hint and tell your bf that you are going on hard times these days (even if you aren't) and that if you say something that hurts him by any chance , ask him not to mind that or take that lightly. This might make him not consider any of your rude acts seriously but instead make him calm you, given the fact that you have already mentioned to him.
3. Walk often, in nature or alone and give lonely time to yourself to calm your mind. During this period, don't try to keep your mind busy thinking on something, but engages in observing the surroundings, the on goings on the road side or observing birds or nature. Stay silent for the most part of your day and give time to yourself. Think about the goods in you and feel happy about that.
4. When you get angry, just say to ur bf that u will call me after some time or the next day and hang the call. Once you hang the phone, do something that keeps you engaged - like watching an inspiring movie, animated movies the best, or do some hobby works like art, sketch or even listen to good music.
I think the above activities should work for you. Cheers and do let me and others know if the above points or something else works for you. Best wishes