I waxed my arms about a week ago, a few days later I had a break out of pimples on my upper arms, I am not sure if this is a break out of pimples or eczema.

Not a break out of pimples, you have irritated the hair follicles on your arm.

I am 18 years old and I had sex September 7. I started my period a week and a half early. I started on the 10. My period ended that Friday, the 14th and I am feeling pain in my stomach a little bit, nausea, back ache, breast feel heavy, sleepy all the time...

We didn't use a condom and I stopped using birth control toward the middle Of August. I have had my period toward the end of August so it's not signs of quitting my birth control...
Am I pregnant?