Test?

so each month is seems like my period comes later and later. I am sexually active so each month when I’m late I buy a test to see if I’m pregnant and I’m not. I’m tired of buying pregnancy tests each month just for My period to start 2 days later.

My cycle usually last 30-40 days. This month is has been at least 50 days. I was spotting old blood a couple weeks ago for like a day.

I’m not on any birth control or have not taken any plan b. Anybody else have this issue?