I'm actually on several WLs right now and I already got a LOR from this PI a while ago when I was in a very good position with him.
Cool. All is not lost. My last undergrad PI was really, really pissed at me, but it didn't matter because I already had LOR in hand. So eh, screw it. Just learn your lessons and move on. I just hope you get in this year

WLs really tend to to move around May 15.
About depression about this process... It never gets any easier. You're going to continue to have extreme challenge and stress. Try to learn how to deal with it now. In my grad lab, it was always expected that you would keep working in lab while in med school. Even if you told the PI you wanted to stay in that lab and that you would pick your rotation project back up, your rotation project would instantly be picked up by someone else and you would be thrown off the project if you were in med school or even away for a month. My MD/PhD buddy spent a year and a half on a project only to get scooped by a post-doc in his own lab and get his name misspelled in the acknowledgements (i.e. not even an author on the paper). They knew he'd be pissed about it, so they just didn't tell him. He saw it when the paper showed up in Nature Somethingorother. Think there's any recourse? Hah! Of course not. My PI expected me to keep working in his lab through third year of med school, which is an absolutely ridiculous request. But he wouldn't listen to anyone otherwise. His response would be, "You're MD/PhD aren't you? You should be doing both research and clinical work. You're just lazy." The same would be said about the research residents who weren't doing research.
And then talk about stress... There's always another major exam that could sink you. There's always some ***hole you have to kiss up to because your grade depends on it. There's residency to apply to. All the while, they hold all the cards. They can absolutely screw you with no recourse. If you fail to match because even though you went on 12 interviews, good luck finding a FP residency in the scramble. If you report a rotation to the dean because it's 120 hours a week and there's a 80 hour work rule (not that it's enforced and it doesn't apply to med students anyways), it'll be you who fails the rotation (seen this happen). If you piss off the wrong attending in residency, every mistake you make can be amplified until they nitpick on you and throw you out, and then good luck getting another residency.
How do you keep this stuff from happening to you? Keep upbeat, doing take things personally, and keep pushing towards your goals. We're bred to be sheep in this hierarchical game. It lends itself to abuse. I can't even count the number of times I was told I didn't get a real PhD because I didn't spend as long getting it or I wouldn't be successful in my field because my PhD wasn't in Physics or Engineering. Or how many times I've heard MDs and MD/PhD doesn't do real/serious research anyways! Think I can argue with these people?! I've tried, and then I get labelled as confrontational and acting like I'm better than them
😕. Teaching is the last thing on the mind of most PIs and attendings, because it isn't rewarded in this system. Rewarded are grants, obtained in part by publishing quickly and often, i.e. not cutting you any slack for things in your life, and on the clinical side, clinical throughput, also not cutting you any slack for things in your life. What if you get sick? Well you better be practically dead to not come into residency.
Welcome to the MD/PhD life. You won't be in any position to have any control over anything until you're in your 40s. Then if you actually do keep doing research, the extreme pressure is on you to keep bringing in grants at 10th percentile funding levels. Good luck getting anything resembling a startup package or tenure. If your money runs out or you fail to ever get any because you were never given a chance to begin with (too much clinical duty, no resources), you're liable to get tossed out on your rear, or at least if you're board certified you can be pushed to the clinical realm without any hope of ever coming back to research. I've heard that story over, and over, and over again. I never knew about it when I was an applicant or a first year because I'd only met happy and successful MD/PhDs. You don't get to meet those who were run into the ground or ****ed over.
What's my point? This is the reality check. Calm down. What's going on to you right now isn't that bad if you do manage to get into a program. Screw your old lab, but only in your own mind. It's worth keeping your enemies to a minimum. Just grin and bear it for now.