I am a 14 year old girl and I just got my first period last Sunday (6 days ago). It stopped completely yesturday except for some spotting. Now today I was in the shower, and suddenly the water rinsed down and there was some blood. I went to the toilet immediately and it was bleeding again. I'm worried that it might not even be my period now, it's reddish mixed with clear, I'm just worried that it might not be my period, maybe something else. HELP?

When you first begin menstruating some irregularity is normal and nothing to be alarmed about.
The following link should be helpful to you.
Menstruation Information - Advice - Tips About Normal and Abnormal Periods and the Menstrual Cycle

Thank you.

I forgot to mention, it's bright red, not heavy, and I have cramps.

First periods as well as other times, periods stop and start up, as well sometimes there is a little blood still left and it comes out on its own, but just in case if it last more than 10 days just mention to your parent about maybe seeing a doctor just to be sure, but don't worry It happens all the time.