Help lady's period 911

So i haven't had my period for 2 months i went to the doctor got a pregnancy done came back negative and i just started my period 2 days ago today is the 3rd day and my period is more heavier than the first 2 days but this time I have a lot of cramps and big chunks on blood clogs is that normal? what should i do? do you girls know what can be the cause of the extremely bad blood clogs? do you girls know anything that can help?