Sometimes I see Як in a sentence. What does it mean? And what does this sentence mean?
It's written in surzhyk and means something like "It is such an awkward situation." Please, don't use it in a real conversation. The correct spelling is "Як незручно вийшло." It can be used when you feel sorry about the situation or in a sarcastic way when you are not actually sorry.
Як means "how".
- получилось, вийшло, склалося, сталося is past tense (something like Past Perfect).
So як невдобно получилось is something like "[oh] how uncomfortable it turned out" or simply "[oh] it's very embarassing", spoken in surzhyk.
AFAIK, this phrase comes from the anecdote about countryside newlyweds: after first intercourse during wedding night the fiance says "Didn't you say that you were a virgin before the wedding?" (implying that it appeared to be not truth) and the bride answers (feigning surprise) "Really?! Did I? Or, it's so embarrassing now" — i.e. it's easy to simulate repentance after you already got what you want in unfair manner.