menstrual cycle

Ever since I had my oldest son, he is now 21 years 3 months old, I've had to take medroxyprogesterone every third month to have a cycle.  I had to take fertility drugs to get pregnant with my second son who is now 14 years 2 months old.  Everything went according to clockwork until this last April.  I started taking the medicine in pill form, but because my husband died, I didn't take my medicine on schedule.  I didn't have a cycle, but I did take my medicine again in July and had a cycle.  I shouldn't have had another cycle until October when I was due to take my medicine again.  However, I had a cycle start on its own in both August and September.  I haven't had one yet this month.  I asked my OBGYN, who knows how long I've had this problem, what could be going on, and the only answer he gave me was that it was a good thing my cycles were starting on their own.  Of course some of my co-workers are saying it could be perimenopause because I'm also experiencing problems with being hot when nobody else is.  I'm 42 years old, and I just want to get an idea of what may or may not be going on.