It's unbearable at times.
The (only) key is self-confidence.
No one is attracted to someone who has the aura of depression on them, to someone who looks constantly worried.
No one wants a mope, or that guy/girl walking down the street staring at a point three feet in front of them, seemingly concentrating on how bad everything is.
Put yourself in the shoes of everyone walking around you on the street, surrounding you on campus, having fun around you at the mall, and look at you through their eyes.
Would you want you if you weren't you?
As for your physical appearance? Confidence > looks.
I've seen lots of 'ugly', 'homely', whatever people walking around looking miserable.
I've also seen an equal amount of plain-to-ugly (passing over the who-am-I-to-judge question atm) people WITH someone, hand-in-hand, married, going out, dating, laughing, glowing, having a life, etc., and it just comes down simply to accepting who you are and being good with it.
On your 'good' days go out and head-count the smiles, the attraction you get. Do the same on your bad days.
My good days, it's great. Now - I don't have a clue what to do with the attention (or as to why the confidence ebbs away), but it feels good nonetheless, and it boosts your confidence and loops back on itself.
As for how to achieve/hold onto this self-confidence, well, that's up to the individual, but I'll willingly take any pointers you come up with...