No period in 2 months HPT Negative

Savannah
I haven't had a period in 2 months I've took first response early results, clear blue digital, dollar store brand test and ones off eBay bulk package from china. 
​All of them say negative! 
​Haven't took a first response it clear blue in 2 weeks just been taking dollar ones the past to weeks. Dose anyone know what might be going on? 
​TTC #2