What are the signs of early miscarriage?

Well I got 3 positive pregnacy tests 8 days ago and my period was duethe 30th of last month. And i was cramping around the time I got my positive but I'm not cramping anymore. I do alot of strenuous things throughout the day cause I have a 1 year old so I'm constantly bending over or lifting things. So my question is if I miscarried would I know? I don't feel pregnant....