I'm kind of in the same boat with you. I have friends but I really dont have a best friend. I've always felt a little embarassed about that. I was always the person that was the "bridesmaid alternate" because they had their best friend, childhood friends, sisters and cousins and I have always been the next in line if they could have more attendants. I understand and all because I appreciated the fact that they told me they wanted me to do it but now that it's my turn it kind of makes it an awkward situation. Some of my good friends are best friends and so I kind of feel weird if I asked any of them to be my MOH... because I know I wouldn't be theirs. I'm not even sure which of my friends are going to make it to my wedding. My fiance' has many friends who he's know all throughout school and they are already planning on going. This makes it more awkward for me because I'm going to feel a bit loser-ish if he has a bunch of his friends there and I dont have any. I know I'll have someone there but I cant help but think about that sometimes.
His brother was married in Oahu last summer. They didn't have a big wedding and didn't have a BM or MOH but we did sign the licenses for them so technically we were the BM and MOH. I'm not planning on having a wedding party but at least I know that I can have his sister in law sign the license for me since I did the same for her and it wont be awkward:)
You definitely aren't alone. I'm glad you posted because I really dont have anyone that I can tell this stuff to.