Want to know...

Ok, so I've had some weird things going on lately.
I know last month I had a period on the first. Me and my b/f were active sometime between the 9th and the 20th. I really don't remember the exact date but I'm trying to remember by other events going on at the time.
I know I've felt like crap for a couple of weeks- at first I thought I had depression. There are some really stressful things going on in my life, so I thought it was just my way of expressing that.
I never really noticed my sleeping habits changed, or exactly when it happened. I'm usually a night owl- I like to stay up til 1 and 2 am playing internet games, washing dishes, reading a book, or whatever. Lately, I've been coming home and taking three or so hour long naps, getting up for a short period of time, and then going back to bed and sleeping all night. I feel like I sleep more than I spend time awake. At work, around 2 oclock I'm fighting to keep my eyes open. I continously think about sleep until 5.
I've noticed my bathroom habits have changed. I go alot, once a day. Now, it's once a day and I'm having trouble.
Used to, I could eat once/twice a day, and I don't normally think about eating.
My back's been hurting alot, and I've gotten heat waves alot, and I'm having palpatations going up and down stairs. I'm 23 years old, pretty fit, and I was going to the gym until the last several months. I am a smoker, but am in pretty good health.
I'm thinking, I'm usually pretty regular on my cycle, I had cramps a few days ago. Should I have started by now?
I want to wait a few more days just in case, but based on this, I'm kinda worried. I really want to know what to think and how to get prepared for whatever is going on.