I've been with my girl for 3 years.

In the last year things have been falling apart and she always says I'm not there for her when she's feeling down. I love her more than anything and don't want to lose her but feel I can't do anything right.

She called me tonight and was upset and wanted to talk (I was asleep as have work in the morning) and when I said I couldn't talk for long she got really mad and kept telling me I don't show her I love her and that I've proved I can't be there for her. Does she expect me to just sit and talk for hours when I've just gone to sleep? Ive said she can call any time of the night but I still have a job to go to in the morning.

She says I have no empathy and don't seem interested in how she feels. I do find it hard and I just don't know why. She takes this any gets mad telling me I always say 'I don't know' about something that's hard to discuss between us. She feels I'm hiding feelings from her about something deeper and keeps saying over and over that I know why I can't answer things and why I say 'I don't know' but she's convinced I just don't want to tell her

I'm so confused, I need an insight into a woman's mind as I'm always wrong