So I don't know what's going on...

I have all the symptoms I did when I was pregnant with my daughter. Nausea, fatigue, mood swings. I waited for my period to see if I missed it and it came. But I was still feeling crummy so I took a test and its negative. I don't know what to do because I really still feel like I might be. Maybe it's still to soon to test? What do you guys think?