Question: Headaches, really tired all the time, feeling nauseated, cramping throughout the day?

Hi I am 20 years old. I have had the bar in my arm for the past 3 years but it is finished in 2 weeks!! I have had unprotected sex with my boyfriend a couple of times in the last 2 months. the last 3-4 days I am feeling very odd. I had brown spotting, headaches, really tired all the time, feeling nauseated, cramping throughout the day which seems to be on the left of my lower stomach.
I have looked up information about these symptoms and early pregnancy keeps coming up. I don’t know what to do? I don’t know if its too early to take a pregnancy test and if i do will it just come up negative automatically as the bar is still in my arm?
Id really appreciate if you could help me out.