Please explain to me implantation bleeding.please answer

Can any of you lady's explain to me about implantation bleeding? I'm confused because I'm on my third month of my period but I still worry about it because I had sex a few months back and I am on birth control so it makes my period light-ish. Ok so my questions are, does it feel up a tampon? Is it dark or red? Does it have clots and is it slimy? Right now I'm on my period and it fills up tampons, some completely other not all the way and my blood is dark and light red sometimes and the clots are slimy and I also have period pain and I'm on my third day of it the last few months it started on the same day and it ended on the same day but my anxiety makes me worry, would this be a regular period?. Please explain to me about this please and thank you!