I'm Having Pregnancy Systoms But Keep Getting Negative Pregnancy Test

I'm having pregnancy systoms but keep getting negative pregnancy test I had sex 16,17 of December And its January 5th. I have cramping all the time and I get nausea and I have constipation some days and diahriha and some days normal .. I went to the er and neg pregnacy test and they can't find anything ..Ik I'm not crazy .. idk what to do .. my period came on the 23 it was due the 22nd and I spotted the 23-24 then I had a heavy period .. then after my period stopped completely , the next day no bleeding then the following day I was spotting pink like blood ..