HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!?

Ive been sick for about 2 weeks now. Started with a scratchy throat, then it went away and became a runny stuffed nose and a bad cough. My nose is like red in a line across it and when I touch it it hurts really bad. Im only 12 and idk what to do... My mom isnt very stable and she said to use my sisters random antibiotics... Which im so not doing. What can I do to get rid of this!? And is it a sinus infection!?