I am a 20 year old college student, no girlfriend, still a virgin so I empathize. I am really shy around girls and it is hard for me to make new friends anyways, so you can imagine that my first year away from was lonely. Since I had no one to hang out with, I would just use my free time to study and after a while I didn't notice that I was lonely. So my advice is to keep yourself busy, to the point where you don't have time to worry about not having a girlfriend. And try not to spend it on anime and manga. Focus your energy on something productive like work, or exercise.

Eventually things will work out. For me after a while I started to make friends, though I still don't that many females friends, I am adding names to the list. Also relatives help too. They have to love you unconditionally, so go to the wedding and have some fun. If your grandparents ask you why you don't have a girlfriend, tell them you are focusing on your career and don't have time for a girlfriend. They should understand and might even praise you.

Besides, haven't you seen 'Wedding Crashers?' Weddings are a wonderful place to find women. You don't have to be actively looking for women, but if something goes your way, why not go for it?