Do you have Toni Weschler's book?
Are you charting anything - basal body temperature, cervical mucus, saliva microscope, cervical position, using OPKs, that kind of thing? Logging your AFs is interesting but doesn't tell you much about when you are ovulating - in your case, it's telling you that your cycles are irregular, which will mean that if you are ovulating every cycle then you're not doing it at the same time each cycle.
Signs you may be about to ovulate:
Egg white cervical mucus - influenced by raised oestrogen levels. Can be easier to spot if you've had a bowel movement (because the pushing pushes it down too). Unfortunately, can easily be confused with semen if you've BD in the last 12-24 hours.
Saliva producing "ferning" patterns if you dry some on a slide and look at it under a microscope.
Your cervix becomes higher, softer, and possibly more open.
You get positive results (test line as dark as or darker than control line) on an OPK.
Signs you may have just ovulated:
Your basal body temperature (which you need to log at the same time every morning if possible, immediately you wake up and before doing anything else) jumps significantly above what it's been for the last 6 days and stays at the new higher level for at least three days.
The luteal phase (time from ovulating to start of next AF) is generally pretty much the same from one cycle to the next (normal range 10-16 days). So if you chart several cycles, identify when you ovulated in each one and establish what your LP is then you will be able to predict when AF is due after you've ovulated in a subsequent cycle.
Some women find that they consistently ovulate on or around the same cycle day, so their cycles tend to be a consistent length and after they've charted a few they can predict roughly when they are going to ovulate in any subsequent cycle. From the brief snippet you've given, it doesn't sound as though yours are like that -- so if you want to identify ovulation then your best bet is either full-on charting or (another popular approach) BDing every other day for a week from when you first notice egg-white cervical mucus (assuming you do).