Spotting when second period after abortion is due

I'm 18 and I sadly had an surgical abortion on the 14th of June! My first period came 5 weeks after and was normal enough, just very painful as expected. Then on the last day of my period I had PROTECTED sex, I saw the doctor the week after to get an app for the Implant in my arm, I did a test but it was negative. My next period was due 2 days ago but instead I've had very very light brown spotting and a small bit of cramping! I am so stressed out over this, it's making me feel sick and I'm panicking big time.  I really don't want to be pregnant again & I'm getting the implant in my arm but  I have to get my period first. Is the brown spotting what I think it is or is it just that my period cycle is completely messed up & it's a light period??