Late period

So I haven’t got my period for almost 2 months, I’m on a pill but I take them on and off, I’ve taken 3 pee test and all of them came negative, what if I might end up being pregnant, I haven’t take any blood test since I have a flu/cold. I asked my doctor if stress can cause not having period or not, my doctor told me that too much stress can cause not having period. I have been freaking out for the past 2 months.