True heartache is one of the worst feelings anyone can feel, and moving on from such a thing doesn't happen overnight. When people tell you that " you gotta just get over it man", it's almost condescending, especially if said person has never experienced what you're going through. Seriously, these things take time.
My solution to remedy a similar situation from a while back, was to force myself to go out with other girls (whether they be potential love interests, or just a friend). You may be bitter about things for a while, and may even ignore advances from other girls, but that fades in time. (Of course, everyone's mileage will vary).
As for "dropping" girls that reject you? It's for the best, but I'd be lying if I said it's something I've actually done myself. It's a lot harder than it seems.