3 positive, 1 negative

Hello Everyone ! Yesterday afternoon I took 3 pregnancy test all about an hour apart and 2 came back with very day lines and a digital came back reading "yes" ... This morning with my first pee I took another test and it said "no" :( Do you think it's possibly another chemical pregnancy ? I have had mild abdominal cramps that are pretty consistent through the day and my breast hurt so bad !!! I would be around 4 weeks if I'm pregnant so getting in to see the OB this early is nearly impossible !!!