So confused - implantation or period?!

I'm just looking for some advice really. So I was heartbroken on Tuesday when it seemed as if AF had arrived - I'd had lots of symptoms and was sure I was pregnant. When it arrived, I had very light pink bleeding with cm to start with so I thought ah! Implantation! Then a period / bleeding started properly the next day so I figured I was out. This felt like my normal period but lighter - still had to wear sanitary towel though so from what I had heard - I was out. Also worth mentioning had cramping too. So weird though as my period stopped completely after 2 days - unheard of for me. Everyone I've spoken to said I can't be pregnant - what do you guys think? Is it at all possible it could have been implantation? 

Thing is I have to make a decision about my job very soon and I'm basically leaving unless I'm pregnant (long story) so I guess I just wanted to make sure before? A trip to the doctors to make sure? I would be about 15 dpo now and the bleeding was 12-14 dpo.

Thank you for your time in reading this and any replies gratefully received! Xx