Doh!
My mind apparently short-circuited due to jet lag - I was fully convinced that my flight from Riga to London was leaving at 19:45, soI arrived to the airport well in advance - at 18:00. Only then I found out that the actual flight that I had the ticket for was scheduled at 11:20. Doh! Sunday evening, nothing works and I am stuck in Riga.
I am lucky to have great friends in Riga who lent me some money and let me stay at their place for a few more days.
Luckily I was able to get a relatively cheap British Airways ticket for Tuesday (<150$ one way :$) online at www.lidot.lv that I could buyout in cash at the day of the flight.
Two days waisted - see subj.
P.S. I am too still jet lagging slightly.