recently she seems to spend lesser time talking to me, what
happened?
It could be due to an increase in workload for her, that is why
she is spending lesser time talking to you.
Of course, if you look at it negatively, it could be because she
has noticed something from you already and is trying to stay
slightly further away from you, or that she has someone else in her
life already.
If you are really keen on knowing why, ask her directly
yourself. But please do not pose a direct question like, "Why are
you ignoring me?".
You should ask her something like, "You seem to chat less
recently, is it due to an increase in workload?"