If the part in front of @ is anything like first name, then chances are they got you just by what is called a dictionary attack. I.e. the spammers got a list of names and just try them out at any domain they know of. I used to watch email logs quite closely for a while and I got a few domains, which only have a very small number of working addresses.
It could also be that someones computer (like inside of BAEC of someone who has emailed you) got infected and the Trojan harvested addresses to which emails have been sent.