How do I know?

So I just got a positive pregnancy test 5 days ago. Today was supposed to be the start of my next period. What are some symptoms that some you you nice lady’s had when you missed your first period that let you know that it wasn’t going to come?.. I have a lot of clear discharge and some mild cramping but no blood. I got a positive test but my brain is still not believing it.. I just want reassurance.