HALP SPOTTED VERY DARK BROWN BLOOD AFTER ALREADY HAVING A PERIOD A WEEK B4

Angel

I already had my period it lasted about 4 days it was very light but now about a week later out of nowhere for the first time ever when I went to use the bathroom I saw in my panties was very very very dark brown blood not too much but enough it was very scary I didn't know what to think or what it could be since I just had a light period a week ago how does anybody have any kind of idea what's going on with my body I did talk to my doctor's office and the nurse said it could possibly be left over blood from my menstrual cycle that I had the previous week I deep down hope it was implantation the entire time but I don't know if that's possible the amount of space in between. I am having other symptoms like nausea constant sleeping but it could also be a side effect of the medicinemedicine im on I'm which says side effects nausea vomiting and drowsiness which are symptoms of experiencing yet could also be pregnancy. has anybody experienced this before please????