Confused, symptoms help.

Rebecca
Had a miscarriage on nov 17. Supposed to have my period on dec 24. I took a pregnancy test the 21st when glow said to. Was negative. Took one the 27th. It was also negative. 
I'm nauseous on occasion, frequent bathroom visits, gained weight and headaches. 
However my stomach isn't right like when I was pregnant with my son and second pregnancy before the miscarriage. 
Any ideas?