Cramps but positive pregnancy test?

So, I was expected to start my period on the 29th-1st and I haven't started yet. I've been experiencing lower abdominal pain. The first night it was exrutiating and has gotten better each day. I took 2 test yesterday, 3 today, all positive. (The second round was an alternative brand, and took awhile before the additional line showed up). I've never been pregnant before and am really worried about the pain I've been having. I heard it could be a chemical pregnant or entopic one? Any suggestions!? Thanks in advance! (I do have doctor appointment tomorrow I'm just impatient and anxious)