When to test??

Danielle
So I was on the pill for years, came off on feb and had my first AF 4 weeks later in March. 4 weeks later next AF in April. Then Mays AF didn't done u til 5 weeks later. Therefore glow haas now put me at a longer cycle and said that AF is due next Sat. 
​I was quite stressed about TTC last month this could be why I was late. 
​When do you think I should do a hpt?? 
​I'm asking as I've been thinking and maybe AF was actually due yesterday and not next sat?
​I'm so desperate to know. 
​Thanks for any advice xx