Positive urine but negative bloods?

I took a test yesterday after 2 days of missing my period, it was negative but today I had a very faint line but still definitely a line!! I had bloods done the same day which indicated my hcg was too low to be considered pregnant at this stage...

I thought blood was more accurate than urine? I understand it might be chemical pregnancy and I’ll go back for another blood text next week but is there any chance given I’ve only just had a positive result that maybe my hcg was too low in my blood?😌