Wolfman moving forward 3

[Wolfman]

I can’t sleep. A situation came up and want to hear what I should do. A friend from my job has a side job. He asked Tuesday if I could work Friday night with him. I said let me ask my gf if that’s ok. Now 2 months ago, my gf signed up to take a GRE test tomorrow (Friday). I thought she told me it was I. The morning because she asked if I was going to be off that day, which I am. She has to take it online with someone watching her live. So I asked her Tuesday morning through text.
Here is the text conversation with some minor changes just because we are on the board like names and exact job.

Me: The guy B, asked if I could work this friday? I would meet him at the ferry at 5:30 and work till 2am. $175 cash.

Gf: And you’re going to be up in time to help me with Baby? lol

Me: Might be a little tough.

Gf: You should consider that. Considering the help I get is minimal.

Me: I understand, but money is tight.

Gf: k

Then last night right before we are going to bed, she says I know you are supposed to work tomorrow night but I just remembered I have the test tomorrow. I said I know it’s in the morning. She said no it’s at 8pm. I said I could have sworn you told me it was in the morning originally. She said no I told you it was at night. And I going to need to you to keep an eye on the baby. I said but her will be sleeping. She said what happens if he wakes up? I said why did you tell me it was ok then to work? I would have just said no to him. She said see you never remember anything of mine. But if it was a game for your son or something for him you would remember. I said I only remember his games because the coach puts it on an app. She said anyway I didn’t say it was ok. I said you said k. She actually said I didn’t say ok, just k. I said what’s the difference? She said k was just acknowledging that you said we are tight on money. Ugh. So I am asking everyone here what do I do. The guy B makes the schedule early in the week. If I cancel that looks bad and he may never ask me to help again which is good money, when I am financially struggling. On the other hand I know this is important to her.
Help!!