Extremely lost and unmotivated in new lab, what am I supposed to do?
This does seem like a difficult situation but don't lose hope!
Moving labs is 100% NOT an option here.
That means that you will have to adapt to your current environment - i.e. to learn some core chemistry concepts. Without them, it is indeed difficult to find motivation to work on a project you don't understand.
I don't have the time, nor the drive, to teach myself years of chemistry I never learned.
Time: I'd say that catching up on the background is one of your main priorities and is essential for your future as a researcher (given the circumstances). Luckily, you don't have to catch up on "years" of chemistry - start off with the areas that are most essential to your work (not specific questions, however, but rather general topics that are closely related to your experiments).
Drive: As you keep broadening your horizons, keep track of all the things you've learned to stay motivated! There will be a lot of things to catch up on but try to notice all those little moments when the knowledge that you've acquired makes your job easier - there will be a lot of them, and they certainly count.
No matter how many questions I ask (and I ask a lot) I don't retain anything or understand half of it because its all upper level concepts to which I have no base to put them on.
Sounds like you already know what you need. Whether it is auditing a class, reading a textbook, or taking an online course, you need some foundational knowledge to build upon. Googling won't cut it.
Most importantly, be patient. It will take a while to become proficient in a new area, but it's certainly possible. Celebrate small victories and use this as an opportunity for growth. Good luck!
I'm going to assume, as you requested, that you're absolutely stuck where you are, unable to go anywhere else. I don't know this is true, but for the purposes of my answer, I'll assume that it is.
Well, sure, you could try to play catch-up with a whole lot of chemistry. But there might be another way out of this.
What if you were to take a step back and look at the various research interests of the PI? Find something that interests you, where you have something to contribute? In other words, find some point of interdisciplinary intersection. And leave the heavy duty chemistry to the people in the lab who trained in chemistry.
If there's nothing that jumps out at you from the PI's publication record or description of current research interests, then try to find at least one paper that uses something he's knowledgeable about, and something you're knowledgeable about.
Or, think in terms of what you want to learn from this guy, that would help you later when you get back to your cell biology.
Hopefully this PI will help you find some intersection with him -- a topic of your own. If not, find someone else in the department to get you started.