Anyone experienced this kind of pain?

I took a test and it was positive. Now I'm back barely bleeding with cramping on my right pelvic area. I went to the ER and it was determined I'm 3 weeks but the ER said its normal. The ER doctor said its my body preparing the finish to my cycle and thats why im barely bleeding. I thought the test was wrong because today is actually my expected period date so I got scared.