I am 17 and around October 26th I have unprotected sex. For the past couple of weeks my nipples have been hard and sore, my back has also been sore, I have felt sick off and on, and I have had a milky white discharge. Are these symptoms of pregnancy?

They can be symptoms of pregnancy, impending period, impending miscarriage (tiny, but more blood than your typical period), the flu, a STD, or just about anything. NOTHING can tell you except a pregnancy test.
Please be tested for STDs and pregnancy, and get some birth control. See if there is a Planned Parenthood near you.
Do a LOT of reading about STDs, birth control, and pregnancy, or talk to one of the counselors at PP.

Why are you having unprotected sex at 17? Odds are you will be left alone to raise whatever child results. Most guys that age run from you at that point. And good luck getting money to pay for any of this from someone who would be lucky to have a minimum wage job at all much less insurance.

Pregnancy will be a possibility, but see what happens when your period is due for November. If period doesn't show, give it several days to see if it is just an off cycle. Try a pregnancy test if you don't have a period for November. Be sure to follow the directions carefully.

You should try a pregnancy test.