I've been doing the same as have had headaches and muscle pain, all negative but did a PCR yesterday to be sure as I've had 3 friends/colleagues test positive this week after negative LFTs
I've had a persistent cough the last couple of weeks but negative lfts. Had to go into work on 9th and got pinged as a close contact, probably from the train so went for a PCR test and have been doing lfts almost daily since.
Not just this morning's - daily tests between now and Tues.
Would be much more concerned if my symptoms were worse, but that feels increasingly like a false alarm.