Late late late late !!!!!!!

Rosie • Can't wait to be married to my King 💍👰🏼 December baby on board 💗💙☺️
Ok so I'm now 61 days since my last period!!!! My last period was on 20th of November  
It's been negative every single day since I've. Been able to test! (Also tested positive opk during my fertile window) !! 
What an earth is going on!? Has this happened to anyone?? 
I'm usually regular, usually have a CD of about 41 days. 
I've just been using all kinds of PG tests, good expensive brands and also the cheapie  ones. Do you think I can go for a blood test to check? Just so confused, haven't got no symptoms of AF of PG 🙃🙃🙃🤔 please please give me some advice because I'm just in utter confusion!