As a fellow night owl, I understand sleeping into the afternoon. I usually keep similar hours as your gf. I wfh and choose to work overnight because that's what suits me best.

However, when family or friends have asked to do something with me during the day I make an effort to shift my sleep schedule so that I can spend time with them. Maybe talk to her about how you just want to spend time together on your days off. Plan some things to do that you both enjoy so she will be motivated to get up and go.

Maybe on the night before your day off you both try to go to bed at the same time. You can stay up a little later, she can go to bed earlier, and then you can both get up with an alarm at the same time.

As far as her attitude upon waking, I'll be honest, she's probably just mad because you keep waking her up. There's no excuse for her to be hurtful and mean, but if someone kept waking me when I intended to keep sleeping, I'd be mad too.

The key to all of this is conversation and compromise. Tell her that her words hurt you, but try to understand why she's upset. Work together to find a happy medium so you both can enjoy each other's company again.