Help? Am I pregnant?

Lulu • June 8, 1989🍒
Okay, so about a week or so ago I thought I was pregnant. I had already had my period for the month though so I was very confused. 
Then, on the 18th, I woke up with heavy spotting and a lot of blood. I put in a tampon and the bleeding continued until the 19th and then cleared up this morning.  
A 2 day period only 15 days after a normal period? What is going on? I had sex about two weeks ago.