possible pregnancy?

I am looking for advice as I am unsure what to do. My last period ended on 12/29/17, according to glow I was to start on 1/20/2018, as of today I still have yet to start my period. However, I have been taking pregnancy tests and they have been negative, my last test being on 2/1/18. However what has me unsure is the past two days once I am up and moving I feel so nauseous, and I actually have puked up stomach bile both days.. immediately after I vomit I then feel fine for the rest of the day. Any advice on what could be going on? Don’t know if I’m just looking too much into it. Thanks in advance!