implantation or preg?

So i have a 26 average cycle and started my period 2 days early. But I never start early- If anything I always start a couple days late.
Also this does not feel like a normal period. Usually I will be heavy my first day and heaviest my second day. This time I spotted, went heavy and spotted again the first day. Now I'm on the second day and I have a heavier flow but it is no where as close to my normal second day flow it is much lighter. 
I have intense lower back pain that won't go away but surprisingly very little stomach cramps if any. 
The blood is bright red and no visible clots. Could this be implantation or is this definetly a period? 
I want to just accept that this is my period but something feels off