Since my miscarriage 5 cycles ago, i have been having very long cycles. they have lasted between 40-45 days, and some anovulatory. what can be done?

It depends: It usually takes time for your cycle to return to normal after a miscarriage . To regulate the cycle, you can try a short cycle of an oral contraceptive if there is no contraindication.

Long cycles: What you describe it is unusuall. Such a long cycle is not something normal. It can actually signal some complications from your misscariage. Seeing a doctor will help diagnose the problem really quick and help you further in your quest to get pregnant again.