Implantation bleeding?!

Ok so my calander looks plain but I just started on Glow and I haven't transfered my information.

On the 10th and 11th I had a very light period (only used 3 tampons).

For the past week my stomach has been gurgling off and on, I can't seem to ever eat enough, and my lower back feels broken it hurts so bad and I'm peeing every 90-180 minutes.

For the last 12 hours when I wipe there's a brown discharge, I've been slightly cramping for 36 hours now. Could this be implantation bleeding?!