17 weeks seem like a very long time, but all of your symptoms sound consistent with what little I know about epidurals. They can have serious and long lasting side affects, even if it happens rarely it can happen. Also, getting a doctor to even consider the possibility that your problems were caused by something they or another doctor did is next to impossible.
I would be hopeful that your symptoms will eventually improve with time, but there are many people on here much more knowledgeable than me. I am sure you will hear from them.