Sounds like it isn't being single that's the problem, it's your social life. It's obviously not working for you at the moment. You need to sort that out and eventually you will meet someone. When I was at school I used to be quite reserved,staying in a lot and it's really not healthy.
From what you've said you really don't get to meet people much and the fact is if you don't meet with lots of people it's gonna take that much longer to find someone suitable.
Are you a member of any societies? groups? If not, think of things you are interested in and get involved. The more things you try the more friends you make and the more chances of finding a bf.
One thing i would say is don't write off clubs and bars. Usually the problem with going to them is the company, if it's not good you won't have a good night. When you develop a good circle of friends consider trying it out again.