Please answer this question, confused woman needing answers!?

Hi there. I am trying to concieve with my partner. I had on the 1st, 6th, 9th, 12th and 15th of November plus a few more times after that and recently. On the 18th (15 days ago) i noticed a tiny bit of blood on the tissue. And about a week ago i was having light spotting for a few days and now it has completely stopped. The 1st day of my last period was the 28th October so im roughly 4/5 days late. Every so often i get a strange twinge in my and a strange twinge on the bottom right side of my abdomem. I took a tesco test three days ago and it was completely negative, not even the faintest of lines. I tested 10pm at night. It was a �3 test from Tesco. Has this ever happened to any of you out there and it turned out that you were indeed pregnant? Although i havent had any sickness or signes apart from late period. I have read a few stories on here about people that have had false negatives. Also, when does morning sickness typically start? Is it around 6 weeks? I just don't know what to do apart from wait.