Confused? Or too soon to tell?

Tested yesterday and got a super faint line...period was due yesterday according to app (normally I get my period first couple days of the month then started this app beginning of month as ttc). I have been nauseous everyday for past 2 weeks (no diet change etc) my boobs are engorged but not tender and I have a little back ache today. I had ectopic back about 5 months ago and we put trying on hold. Now I'm just trying to figure out what the heck and if I could be pregnant and just tested too soon?? I called ob nurse and she suggested I just give it another week then come in for blood test if still no period. Any one else have this happen and what was outcome?