please help, i am worried.

can anyone explain what's happening to me? my whole cycle suddenly changed. it started from being late for 3-4 days, but then i got no period during september, and now also november.

read about cryptic pregnancy so now i am 108294892 times more worried.

• last time i had sex was may, and it was protected
• i experience cramping on left side of my lower abdomen
• before i used to have cramps and lower back pain as pms, but it changed to sore breasts after having sex, however it disappeared last month, and this month too so i really don't know when i'll get my period by now
• stressed nowadays and skip meals quite often so i think that's one of the reasons why it's fucked up somehow

and now, i was supposed to have my period this week, but it's really late, and i think i'll get mine at december at this point, but can anyone share their experience otherwise? getting really nervous since i was really irregular before, became regular and now it's getting fucked up again. i am going insane.