Thanks to all of you who replied with wonderful advice.
I am coping much better now and I think I can handle it from now on.
My panic attacks aren't as severe as they used to be a year ago, and now I think they are actually starting to get even better than last week.
Also I want to clear up something- I do not bother my boyfriend with my problems (unless it's about family or school which are minimal) and he is free to do whatever he wants, so I'm sorry if this complaint came off as "needy" in any way. It was not meant to be that. I just needed to express myself and writing is not my strongest point.
I will be closing this thread soon, so no more comments please.
Again, thank you for all of your supportive help! I'm sorry if this bothered anyone in the slightest.
Like I'm sure others have hinted at, you need to figure out some sort of coping mechanism for these situations. While it's great that your boyfriend is supportive, you can't depend on him so heavily. It's probably stressful for both of you that way.
I don't have an easy answer for finding a coping mechanism, since it sounds like you've been trying. If it helps, just keep assuring yourself "He's just going to see his parents, he'll be back in a few days," and find a way to keep your mind off of it. I know I personally like to play video games to pass the time when I have free time. Otherwise, perhaps a counselor could recommend a better way to manage the anxiety.
I am going to say that I don't really understand your panic attacks about being alone...? But i say keep working at the being okay alone thing and to do the same as everyone else has told you on here. xD
I think for the future of this relationship (and maybe others) you gotta figure out a way to be comfortable with just yourself, and not need someone else to have a basic feeling of security. That's not a burden that you should put on another person, it's something everyone needs to carry on their own.