Implantation or period???

I am meant to get my period on Thursday.

Last month was 21 days, the previous 3 months were 24 days consistently.

I experienced a bit of bleeding yesterday and today but it’s now like non-existent on the pad now. (I thought I would wear one the side of caution).

Could it be implantation/ovulation bleeding?

I’m going to test in a few days but this is not how I normally would have my period- it’s usually very constant /moderate and constantly needing to change obviously.

Thoughts? I feel super exhausted like absolutely stuffed, bloated, headache, experienced diarea today, cramps as well.

I never get cramps , headaches or exhaustion in periods.

I am hoping for the best!! I know you can get a positive on the back of this.. and I know implantation can be mistaken for a period given it’s around similar timings.