My girlfriend of 5 months has started acting strange the past few days. It all began monday night when i text to say how was she and she sent 2 brief texts before saying she was heading out with her mates in college(first night back)that was fine.So i left her be yesterday and no contact which was strange because we talk everyday. So i sent her a cute text this morning and she replied hey babe but then said she had a lecture and chat to you later.I waited all day until a couple of hours ago and said how was your day?(no big deal right) and again nothing back. Am i worrying about nothing? Ladies what do you think? Should I just leave her alone now and see what happens? She knows i really really care about her

I am 24 and she is 20.