I am irregular too, but I am certainly not one to be suspected as not ovulating....I never have any problems getting pregnant lol.

You may also not ovulate (release an egg) every time you have a cycle because of several different reasons, and you do have 2 ovaries, so you could ovulate every other month if one did not hold any more eggs. It's hard to tell that's going on unless you went to a specialist.

I don't think that thick dark blood is anything to worry about either, especially if you are a little later than usual.

You need to try and be active and move the cycle thru your body, ever month is different because of body chemisrty, diet and as u get older it doesn't get any better and blood gets darker, (aging), use heat (heating pad)to help. so u need to exerise moderately and eat smart be active.
your body needs to do what it needs to keep u healthy, and shedding as it is knowen, helps the natural ral process,and that is sometimes why you have sharp pains and if you pay attentution in the bathroom, you may even pass clots..And thats normal
Irregular Periods can be du to stress to, exercise , ect. Stay Warm and good luck all the best ww