Advice as confused

On the 6th this month I done a pregnancy test and got a faint pink line. So Sunday morning I retested to make sure on another test and a digital and both said positive. On the 13th I had some bright red blood when I wiped went up the hospital and they done 3 tests and all came back negative. I got told it must have already gone (chemical I am guessing) and to go home and re test in 10 days. Since then the last day or so I have been spotting on and off (only when I wipe) and it's been brown and brown/pink. Today I thought I would do a test this morning just so I could see the negative for myself but it was positive (blue line).I am just confused to why. Is it because they tested in the evening and I had been drinking lots of squash so urine was weak? Are home pregnancy more sensitive? Could it be just some hormone is still in system or could hospital be wrong? I will test again in 10 days but just wanted to see what others thought.