Am I having a chemical pregnancy?

So my lmp was 6 weeks 4 days ago.
I took one test 4 days ago.. And clear positive.
Took the other yesterday and really really faint positive.
Both fmu. But the night before I did drink loads of water (if that makes a difference)
Should I be worried??
Has anyone else had this problem of the test going lighter, but when on to have a healthy pregnancy.
I keep reading about chemicals!!
But I don't have no cramps, or bleeding
Only back ache.