Hi Steph,
I also ride alone most of the time, but competely understand it is a personal choice. I made that choice after finding myself able to ride when no one else could and if I waited to ride with someone, my fitness would disappear waiting. Sometimes I get a little creeped out, but try to make smart solo mtb. choices (i.e. don't do the technical crazy stuff alone, but still make small improvements). I've also found other people to ride with through biking alone, you see someone else out in the mountains alone, you talk and you've just found a new riding buddy you might not have meet if you were with people.
Good luck!