Could I be pregnant or over thinking it??

Hey I need advice. I’m 8days going on 9 late on my period I took two dollar tree pregnancy tests but they came back not pregnant. I started seeing my discharge more often now and it never happened like that with my period before I have been having headaches I have small cold sore breast an I’m confused as to what’s going on with me I bought one more test I haven’t took it yet cause I feel like I need to use the first pee in the morning type thing idk I really am scared can someone help me out as to what to do??