Don’t understand my cycle

My cycles have been getting shorter each month by one day. I finally got to a normal cycle at 34 days, ovulating on day 20. All of a sudden my last cycle was 38 days and ovulated on day 24. Now this cycle, I haven’t caught my positive opk yet and started testing on cd12. I’m at day 35.

I’ve been nauseated all day/night for 1 week. I had a positive test (very faint) or maybe an indent, a day after the nausea started and all negative since.

Why am I still nauseated? Eating makes me feel better.

My first baby, I had an abnormally long cycle and didn’t get my positive HCG until 20 dpo (from what I thought was dpo)

Is that common? Anyone else in here consistently get late positives on pregnancy tests?? Later than the 12-16dpo that it usually is?