Confused (TMI) opinions welcome!

Krystal
I usually have 37-40 day cycles. I was suppose to start on 1/2 and then on 12/27 (10 dpo, 6 days before I was suppose to start, I spotted (dirty brown) and then got more flow on 12/28 and 12/29. Never got heavy and it stayed mostly dirty drown. A regular tampon probably would have lasted me all day. And then on 12/30 spotting still dirty brown. Not enough for a tampon. And I cramped but they weren't horrible. I am confused because I never start early especially not a week early and it just seemed odd. I don't believe implantation would last that long so I marked this as a period in Glow. I don't have children and I am new at TTC. Could this have been implantation or just an early weird period? Would I be wasting my money on a test?