Hi Wondering If You Could Help Last Cycle Was Nov

Hi wondering if you could help last cycle was Nov 23rd 2015 one week later did hpt and came up positive on CBD 1-2 weeks one week later I did 6 more hpt all negative went to contraception clinic and had a test it was negative. During this time I had very bad pains but no bleeding which I took course of antibiotics for as I was having very bad pains. I have not had a cycle since light dark discharge when cycle was due but only for 3 days. Had internal ultrasound 13th Jan showed sack implant around 4 weeks had 2 blood tests done both negative?? I don't know what is happening can you give any advice please?
Thanks in advance