2 periods in a month....what?

I'm 21, and for the most part my periods have been regular, give or take a couple days early. I was stressed out I think during my regular period and it usually lasts 5 days, it was a little heavy the first 2 days and then not much the last 3. I did wear tampons day and night, never wore a pad at night like I usually do. Anyway fast forward 2 weeks I started again except this time it's really heavy mostly it's in the mornings and gets bright red. I didn't have cramps this time, my breasts are sore which usually happens before I start my periods. I'm supposed to start my regular period next week. Anyway I also had my sinuses kick in and I never took syrup for it until this past weekend. I did have sex the day before I was supposed to ovulate but it was protected, I'm not on birth control though. This is the 5th day of this so called surprise period and I need it to end so I can make a trip to the Gyno. Anyone else have this problem I heard other girls did and I am freaking out since this never happened. It sucks and I get worried. Oh I also have a bad diet. I'm a smaller girl so I eat junk haha. So stress, my sinuses, junk food intake, and I've been drinking more alcohol is what has happened recently but I'm still freaking out.