I'm 40, 2 DSs (5 and 3), normal cycles and pretty regular since having the boys. Usually have a 27/28/29 day cycle, and as I charted my fertile periods while trying to conceive, I know I generally ovulate between days 13 and 15, usually have a luteal phase of about 12 days or so. I've never had much in the way of ovulation pain but I can usually tell that something's going on down there IYSWIM.
When I was pregnant (all four times, counting 2 MCs first) I had very early indications because my ligaments connecting uterus with, um, pelvis??, would 'twang' and generally ache. GPs never believe me, but I would have these 'twangy pains' and aches from about week 5 of pregnancy. All four times. I was also very (over)aware of activity in my uterus while pregnant and could feel it sort of 'seething' - not a great term, but it always felt very busy in there in early pregnancy.
I know I'm not pregnant now (or at least, if I were, I would be so far gone as to virtually be having it now! Haven't had sex since summer) and have menstruated at more or less normal intervals. (nope, haven't peed on a stick. Please don't tell me to! Honestly don't think that's it.)
Ok, so last cycle I had unusual amounts of discomfort in my pelvic area, pain particularly to one side (right) and general lower abdominal tenderness. It went on for days - starting at about ovulation time (I had the mucus to back this up) and went on pretty much until I started bleeding. I also had some 'early' bleeding about a week before it started properly - bloody mucus and some actual blood (I use a mooncup). I do sometimes get a sort of 'show' a few days (3-5) before my period starts in properly and I'm used to that, but this was a bit different - more, and earlier.
Period started a few days earlier than 28 day cycle, but was normal. And now again, I've got this pain and tenderness following ovulation (last week). As you'll have gathered if you read this far, I'm a bit over-aware of what's going on down there, and also a worrier. 
I'm convinced that something Not Good is happening. Does this sound anything to worry about? I'm thinking cysts, but at the back of my hypochondriac head I'm also fretting about ovarian cancer.