Epididymytis from vasectomy?

I had a vasectomy about 1 year ago and everything was working fine, but now, a couple days ago, my left testicle is VERY tender and it hurts unless I support it. Literally, the tenderness sucks really bad. Also, I might be paranoid, but the left one feels like it is a little swollen...infection perhaps? Epididmytis? I have no idea. Wondering if this is common with vasectomys or if perhaps its just nothing and the feeling pass.