pregnant or not?

I'm 18 DPO. I had light brown spotting for 18 hours at 12 DPO and then no period. My boobs are sore and I'm cramping and bloated. I took a pregnancy test on Saturday afternoon that was faintly positive. I took a second test Sunday morning that was negative. Also took digital tests on Sunday and Monday mornings that were both negative. But no sign of my period and the symptoms are not going away. What should I do?