Weight loss, low energy, brain fog

Y’all. I have been vegan for 2 months and I’ve lost just over 15 lbs. I have significantly less energy and so much brain fog, and I’ve also felt physically weaker. I feel I didn’t really plan this stuff and honestly was more scared into it. I watched the Dominion documentary and couldn’t even get thru 12 mins. I was shaking and nauseous and sobbing and immediately went to Whole Foods to get vegan food for my new diet. Anyways as I gave reason to previously, it’s not going as well as I’d hoped. I’ve even tried out the 80/20 rule as of about 2 weeks ago (80% vegan, 20% vegetarian) Which has made me feel guilty. I also have ADHD and actually cooking meals every day takes so much out of me as opposed to easier frozen meals that are more sustainable for me. But they don’t tend to be vegan and are hard to find. I try to include things that are rich in B12 for instance but I’m not seeing much progress and I feel like shit tbh. Only good thing to come from this is I have clearer skin lmao but what do yall do? Any advice or specific things you do to help this issue?