home pregnancy tests

So I've been feeling off (nauseous, sore boobs, frequent urination, darkened areolas) and I had a VERY light period. My symptoms didn't go away, so I took a home pregnancy test on Thursday with clear blue. I got a faint positive! Then on Friday evening, I took another one, with first response, and it was negative. So I took another one with first response this morning with my first urine, and it was also negative. Does this sound like a chemical pregnancy or could it be the hook effect, where my hcg is too high or has already switched to the type the test doesn't detect? I'm not bleeding, which makes me think maybe it's not a chemical pregnancy...? I'm still having the symptoms, though. Has this happened to anyone else? I called my drs office this morning and the nurse suggested I wait a couple days or a week to retest again with the first brand, and go in for a blood test to confirm if it was positive. Any personal experience that you may have and could share would be greatly appreciated!!!