Just a thought, I was having really long cycles like you 70+ and my gyn wanted me to start taking clomid and as it looked like I wasn't going to gat a new cycle happening by myslef he put me on the pill for 7 days (2 tablets a day) then I had to stop taking it to bring on AF so I could start the clomid. Maybe your FS will do something like this for you?
Yeah i think if my cycle doesn't end soon this is what will happen.