Need some advice abit confused

I needed to go for an early scan today because after me and my partner had Intercourse on Saturday night I started to bleed On the Sunday morning. It was only when I wiped I seen it, it was like a mucus blood and it continued all Sunday though to Monday again no pains or blood clots. So before I went I took a clear blue digital and it came out positive so when I went the nurse couldnot see anything I had the belly scan and an internal scan. I took a pee test and that came out negative but because I had my clear blue on with me she could see mine was positiv, so she took some bloods. 2 hours later she called and said I have some pregnancy hormone in my blood and I have to go back Thursday for more blood tests to see if the hormone is still there. Has anyone else had this? I am really confused as to why mine said yes my blood said yes but the pee test I took in the hospital said no