Oh lawluddy what a nightmare. The waiting in a normal length cycle is a nightmare, let alone having to wait for months just to get af. Do you have a Clearblue Fertility Monitor and do you know if you're oving? If not might be worth getting one (they're v cheap in Tesco at the mo) just to see what's going on with your body. I would definitely push with the doctor too - your cycles aren't normal, so they should be testing to see what's going on. Lots of luck.
xxx