IMPLANTATION BLEEDING? TMI

Hey All. New Here. 

Thought this would be the best place to go for advice.

So my period began on the 18/02/18 and I got spotting on the 07/03/18 (I don't usually spot) The blood was mucusy/brown and then went to light pink, I only had mild back aches. This lasted for 2 days on and off and cleared up by the third. According to an ovulation calculator this would be too late for ovulation bleeding and it's more likely to be implantation? As I would of ovulated around the 27th - 2nd march (roughly) There was no blood clots nor fresh blood and went from brown to pink when I wiped.

I have no hormonal imbalances/I've also had a recent ultrasound so everything is working fine within me as it should be I'm only 22!

Me and my partner use the pull-out method which has worked perfect for us so far, kinda reluctant to test because I've had "feelings" before which turned out to be negative.

Anyone had a similar experience? I've never been pregnant before or at least been aware, but this is really strange for me to have mid cycle spotting.

The only symptoms I do have is some fatigue ( but then again I always nap a lot!) but I do feel extremely calm, my mind and body feel completely relaxed which is a new thing for me!