Hi, I Am 9 Days Late For My Period Which

Hi, I am 9 days late for my period which is extremely rare for me. My last period was the 7th December I am always on time if not a day early. I have had nausea and sore boobs. We had sex on the 22nd, 25th and 27th Dec which is when I thought i would be ovulating (we hadnt started tracking it properly yet). I had slight bleeding for a few days on the 17th Dec which was odd but we were flying back from Hawaii so Doc thought it could have been due to travel. I spotted VERY lightly on the 28 Dec for a few days. I didnt need to wear a tampon or anything just saw it when I went to the toilet. I am getting negative HPT's and had a negative blood test on the 7th Jan but the Doc said it may have been too early and to wait two weeks. Is there any chance I could be pregnant? I have noticed slight spotting today