It's a smiley face, imagine it sideways, the x is supposed to be scrunched eyes and the P is like the :P smiley.
xP is basically :P with the eyes closed.
DNA in text talk means "did not attend" or "does not apply."
I'll text you later.
BLAM mean
It means can't talk now
Before.
booty
Tomorrow
it stands for what
no problem
tyt
Si
It can mean anything that start with ctb ( :