Cycle gets longer every 2nd or 3rd time?

I’m 17 and my periods have always been on time like clockwork, but back in May was the last time that happened. I had no period in June, but it came regularly in July and August. Skipped September and it started again today. Both times it skipped, it was 7 weeks late. Lighter flow than usual paired with the regular severe cramps. Should I be concerned it’s skipping 7 weeks more and more often?

I also show symptoms for ovarian cysts/ PCOS/ endometriosis but mom is convinced I’m just fine