Always had regular menses, lasting 5 days, every 28.now irregular, long cycle w/heavy long bleeding during time of "ovulation." i'm 45. what is cause?

Peri-menopause: It is likely that you are entering the peri-menopause. The years prior to menopause women will frequently complain of longer cycles, irregular bleeding, missed periods. See your gyn to confirm that this is what is happening to you and to rule out other conditions that can cause heavy bleeding and mid-cycle bleeding. This is very treatable.