When I get my period I feel like I've been hit with the flu, why?

For over the past year when I get my period I feel like I have the flu; body aches, headaches, nausea, chills, exhaustion, the whole deal. I'm fifteen and have had my period since I was twelve. It's always been heavy and it's always lasted five to seven days.
How I feel has been getting worse... can anybody give me possible answers?

I forgot to mention I have almost non-existent serotonin levels which could effect this.

That sounds to me like menstrual migraines. When people talk about migraines, they tend to emphasize the headache aspect. But it's actually a whole body problem, with nausea, chills, exhaustion, hot flashes, aches, etc. But even though with the chills and hot flashes it feels like you have a fever, your temperature won't be elevated. It's also been noticed that migraines tend to be accompanied by low serotonin levels, so it's particularly notable that you have mentioned that you have that, too. And more: when you are having your period, your estrogen is at its lowest level; and rapidly dropping estrogen can cause migraines. So it seems to me that this confluence of events all indicate menstrual migraines. You should see a neurologist to be treated for the migraines. Unfortunately, gynecologists tend to not know much about menstrual migraines, since the brain isn't their department. Neurologists tend not to know much about periods, because they're not gynecologists. However, a neurologist will still likely be able to help you with the migraines by giving you preventatives as well as painkillers to use during the migraines. In the meantime, until you see a doctor for treatment, you can get some books about migraines, and you can take some over-the-counter preventatives: magnesium (200 mg or more per day); vitamin B-2 (400mg/day); and Co-Q10 (200 mg/day).
Good luck!

If it's that bad, you should talk to your doctor.
You can go on birth control that stops symptoms of PMS and gives you short periods, like Yaz.

It's like that for a lot of my friends. Ask your doctor if there is anything helpful he can perscribe you!:]

midol