So, let me get this straight.
You and your boyfriend have an argument, which is understandable, given how you're both under a lot of pressure, and after a few uncomfortable words exchanged, you block him and delete his number? And you think that it's going to make the situation better or improve it in any way? You think that you're going to get through this thing unscathed? No, you're not. He might have said something negative, yes, but you blocked him, you ended it.
I suggest you talk to him properly and go over it. No matter how stressed you are, or how much you have to study, you should be able to talk in a respectful and loving manner. If you can't - break it off, go your own way. Neither of you seem mature enough to handle a serious relationship and this situation only proves it further.