I would make a GP appointment and get a referral to see a FS. The FS will do some tests and work out what the best route to go is.

I used Clomid (pregnant on 4th cycle of Clomid), I had cycles like yours. Long, irregular, and I wasn't ovulating and the FS found I had PCOS, my hormones were all over the place and I needed monitoring and ultrasounds while I was on the Clomid to make sure I didn't develop OHSS. I also needed a HCG injection to pop the eggs out as my hormones just didn't do the right thing. For that reason, I don't know that a GP will (or should) just prescribe Clomid to you without any fertility investigations or monitoring as it can have some nasty side effects and you definately don't want OHSS.

But go have a chat with teh GP about it for sure. They might be able to recommend something else.