Positive test followed by negative HELP

Hey ladies so the first day of my last period was September 2nd. I’ve been pretty consistent since having my first baby last year. So about a week after I missed my period this month I took a few tests and they were negative. Last week I took a digital one and it said not pregnant. Well two days ago I took my last digital test and it said pregnant. So I ran to the store and grabbed a 3 pack of different tests and they all said negative. Yesterday morning I went up to the ER and they did a urine test and it also said negative so I’m just really confused. I’ve been very tired lately and nauseous. Today I started cramping and I just feel really sick to my stomach. I do have an appt scheduled with my OB on the 1st of next month. I’m just not convinced until my period actually arrives. What do you guys think? This isn’t a planned pregnancy but I would obviously be super excited if I were!