Late late late late !!!!!!!

Rosie โ€ข Can't wait to be married to my King ๐Ÿ’๐Ÿ‘ฐ๐Ÿผ December baby on board ๐Ÿ’—๐Ÿ’™โ˜บ๏ธ
Ok so I'm now 61 days since my last period!!!! My last period was on 20th of November ย 
It's been negative every single day since I've. Been able to test! (Also tested positive opk during my fertile window) !!ย 
What an earth is going on!? Has this happened to anyone??ย 
I'm usually regular, usually have a CD of about 41 days.ย 
I've just been using all kinds of PG tests, good expensive brands and also the cheapie ย 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 ๐Ÿ™ƒ๐Ÿ™ƒ๐Ÿ™ƒ๐Ÿค” please please give me some advice because I'm just in utter confusion!ย