I was infected and treated, and seem to be fine now, but I get headaches/feel tired/etc – is it connected?

It could well be connected. There is currently a lot of research being conducted (including by the LIC) into the persistent state of the infection. Humans cannot become carriers in the same way rats are, however there is evidence to suggest the effects of an infection can last for several years after apparent recovery. For more information see the Persistent infection page.