Don't guess such a thing out of thin air. Her signature on qq can only show that she has inner pain, either at work or in life. As a boyfriend, what you should do now is to care about her, care about her, let her speak out her inner sufferings, share them with her, face them together and solve them together. Don't speculate on her mind with all kinds of suspicious ideas. Your guessing method will only dilute the feelings between you. Even if it really hurts her, what you should do now is to have a good talk with her, let her speak her mind, ask the question clearly, and then think about the solution. Don't be paranoid. Talk to her early and make things clear. That's the best way now!