NanoBeta,
I can only add to what others have already mentioned here. That is - we all, at some point in our lives, fall in love (sometimes madly, sometimes not) and when that ends, for whatever reason, we feel as though we have lost something major as if we lost a part of ourselves. Well, in a way we may, because we hold an important place in our hearts for those that we love and when this ends, not through our own doing, it hurts deeply. In addition, one of the first things we do is start to blame ourselves, like we caused this to happen and how could we have done such a thing to ourselves - we start to feel, either conciously or unconciously a certain (unfounded) guilt.
These hurt emotions, sense of loss in our lives combined with guilt that we may have caused it can manifest itself into physical situations (heart racing, itchy skin (hives), rash, irritablity, repetitive activities, etc.) which can fester if not checked.
My advice to you is to put this into perspective - yes you loved this person deeply, or madly, but for whatever reason (perhaps one you may never know or understand) they ended it, and you have felt the pain of the loss, but now you must put this memory away and move on. I realize that this is easier said than done, but you must try.
Lastly, you are not 'pathetic' and please don't degrade yourself with that term. You are a human being with actual feelings and emotions and you have felt pain. Move on and enjoy the world out there. You may find that all these ailments will subside in time. Of course if they do persist, you should always get them checked out by a doctor.
I really hope that this helps you, feel free to chat with me anytime on this.
Wendy