Body adjust or pregnancy symptoms

Kimberley
Hey girls im new to this site i have an essay lol and sorry for tmi... i had the implant out on 19th november 2015 also came off the pill (i had the pill to control my periods)... anyway a few days after i had some spotting then started to bleed on 25th december and stopped on 27th but it was lighter than my normal period did a test it was negative... since the small bleed i had sex on 28th dec, 30th dec, 1st jan, 3rd jan and 5th jan... had spotting on 29th dec and 2nd and been having symptoms like backache, heartburn, bloating, headache and mild cramp in bottom belly and i feel pregnant but tests show negative with some having a white line i know its probs too early to tell.. my question is, is this to do with my body adjusting or could i be pregnant and when would i get a positive result if i was pregnant... my af is due 22nd jan xx