I'm bf my 13 month old and she still nurses pretty frequently throughout day and night

I got my cycle back at around 8 or 9 months, skipped a month, and then have gotten it back every month since then. I haven't been keeping track except for last cycle. The first day of my last period was May 1 I JUST GOT MY PERIOD TODAY? WTH? Last week I had all sorts of right sided mild cramping/sensation/bloating (prob was ovulating)....and tons of fertile CM. If I "O" last week, then how did I get my period this week? I never had a short luteal phase before and I know that this is not a good thing if you ever want to get preg again bc u have a higher chance of MC right? The month before I also had the same sensation by my right ovary. Is it true that your ovaries alternate each cycle?
Prior to this pregnancy (my second)....have had clockwork cycles and pretty much my entire life.
DH and I are still using the pull out method. He is older and has used this before with success. I'm pretty sure there is no sperm in his pre-ejaculate bc (from what I've read) some men dion't have any mobile sperm in their pre-cum and especially if they have urinated in between times. (dh always does bc, lol, we never BD more than once every other day...TMI) Also...his timing really is perfect. He pulls out without even beginning to ejaculate.