I'm certain I've got it again.
The wife of a guy at work I was talking to (I was wearing a mask, he wasn't) later tested positive, 4 or 5 days later I developed the same symptoms as I had the 1st time (I hadn't fully recovered from the 1st one, still had a mild headache and mild fatigue after six months).
I did a test this time but tested negative. Its possible I didnt do the test correctly, also apparently it's only 70% accurate idk, but I passed it to my Mrs who has been shielding, fortunately she only had very mild symptoms for a couple of days, and it's also been pretty mild for me compared to last time, went through several symptoms quite quickly over a few days, just left with headache/dizziness and fatigue at the moment.
I've got an antibody test to do next week, hopefully it will at least prove that, despite the negative test result, I'm not bullshitting.