Hi huni, i am in the same boat. I have always suffered from irregular painful periods, ranging from 28-50 days. Have you ever been tested for endometriosis? That is the reason for mine being so irregular. Definitely push for your doc to see you, dont allow it to go on and if the GP cant help get them to refer you to a specialist.
In my opinion you should change your doc.
I'm in the exact same boat as you! I've had pcos testing which was neg. and thyroid testing which came back normal to! My cycles range from 30 to sometimes even 50 days and I have no idea why. I too am on 24 dpo and still no period. Ugh. Did yours ever come?
If i dont start soon I'm going to definitly try someone else. did you always have irregular periods?
Shame man. I would personaly go and see someone else. Its not normal for your periods to change so drastically. When i had big changes i went to the doc and found out i had cycts and a non cancerous growth on my cervic. I think u should try see someone else. Good luck