spotting

Okay so I need help! in May I had a d&c; for a miscarriage. they think just a chromosome issue. then in september I had an ectopic pregnancy and had to remove my left tube. I had one normal period after in october but forgot to track it. then in November I didn't know when to expect my period got scared and tested it came positive ( took 2 digital) and went to the hospital their test showed the faintest positive one one per test they did two. and then a blood test showed althe smalled amount and an ultrasound showed nothing. I never got a reason for this. well now I had my expected period starting the 18th and it still hasn't come. the 19th I spotted light pink for a whole day and I took a test today that showed the faintest positive. I did take a test test a week before the 19th to the check and it was negative. do you think I had implantation bleeding...could i be pregnant?!