Ok, let's try to break it down a bit more than just the "talk to her" and "she sounds perfect"-responses, because one's been used enough, and the other is just completely irrelevant so long as OP doesn't enjoy it.
OP, it's obvious that you're not objecting to her playing a game. It seems that when she does it, you feel it affects the rest of the relationship. It's time to say that to her. You're not talking to her to say "you just smoke weed and play all the time", because that's judging her for what she's doing. That's not what it' about, so instead try and talk why it upsets you. If you feel you miss the companionship of cooking together (if you did that), or if you wonder why she stopped cooking - ask about it. Maybe she just grew tired of being the one that cooked?
Focus on figuring out what's going on. Maybe she's upset about something, and has surpressed it behind this game. Maybe she's not. Let her know you're there for her, but that you feel it's tolling when you're the only one keeping things tidy and that's making food etc. If you are doing that. Let her know you miss taking walks and doing things together, and that you'd love to do those sorts of things for her. Maybe she's feeling she lacks the energy to do those things herself? If you speak with her and realize that's what it is, maybe you can look out for her and you figure out what fun things the two of you can do together. After all, if you suggest doing something she'd really like, it's much easier for her to do it, than to figure out what she wants to do and then plan it, if she is feeling that she doesn't have the energy to do it.
Don't just let it simmer like this. You have the right to be unhappy with the way things are, but not in the sense that you should judge her for what she's doing, but rather that you wish to look out for her and the relationship in a way where you both look after each other.
Maybe the weed's irrelevant. Maybe the game is irrelevant. Maybe what you care about is that you're not doing stuff together. Maybe you've become to reliant that she cleans and cooks, and haven't noticed that you haven't been doing those things, yourself? It's not cool that she neglects the relationship, but it might not be malicious. Maybe she's just reacting poorly to something she hasn't been able to talk about.
Be there for her, now. let her know the current situation is bothering you, and hear what she has to say.
if op is serious this is a good thing here