Smurfie to the rescue! I try ...
First of all you need a hug ... So all i can do is give net hugs, but since you do'nt really know me, i figure this is the best kinda anyway **hugs** !!
Next, don't be so hard on yourself. Breakups happen and while they're really hard and really suck, they're not the end of the world. You'll find someone that WILL give their whole heart to you and will expect nothing less in return.
It's really good that you were smart (for lack of a better word) enough to realize that your relationship w/ Alex wasn't working out. What i don't understand is why you need a relationship ... ?? Going out one nite for dinner or a movie or even the "friends w/ benefits" way might be easier on you at the moment, than having a full time "relationship" w/ someone.
Finally, it's okay to feel sorry for yourself. Everyone does it, but there's also a time when 'enough is enough'. Have a bath, paint your nails, go for a 'nite out w/ the girls', ... do something to make yourself feel good. Volunteering is also a great way to go (part of the reason i'm here, to be completely honest) b/c it makes you feel good to know that you're helping someone else.
If your "feeling blue" persists for more than 2 wks along w/ changes in sleeping and eating habits, it may be time to go to the doctor to discuss the likelyhood of this being caused by depression. From your post, i don't see this as being the issue, as this looks to be mostly circumstantial (not that depression can't be circumstantial ... it can, but it doesn't have to be)
Best of luck, sweetie. Email at firstname.lastname@example.org if i can help you out at all or just give you someone to vent to ...
I have this nagging fear that everyone is out to make me paranoid.
In a Smurf's world ...