I have had the same thing going on. I found out last week that it is a fibroid causing my long AF's and the spotting that is happening between and before AF. My last cycle lasted 41 days and the ones before that were 34 days...I wish you luck in finding some answers. I would go to the dr. just to get checked out though..
I would go to your ob/gyn and have them check your hormone levels, or at least let your Dr know whats going on to see if he/she wants to order any lab work or tests. What have your cycles been like prior to this? Are you on any birth control? Sometimes bc can make you spot and have weird cycles.