What platform are you playing on? What difficulty? Do you have all the free DLCs(Retaliation, Resurgence, Rebellion, Reckoning, Earth)? If the answer to that last one is no, you're very limited in who you can play with, since the game with only pair you with people who have the same DLCs installed. They are all free, so if you don't have them yet, get them ASAP.
Destiny carved a little into MP, as did the new DA:IMP, but for the most part, it's still going strong. I almost never have problems finding people to play with, on Silver and Gold. Haven't touched Bronze in ages, since it's just too easy. I'm on PS3, where we were also hit by Destiny. If you're PC(I believe you mentioned as much), that shouldn't be an issue.
EDIT: the multiplayer part of the forum is also still very much active... maybe you can look for a few people to play with there?