I’ve been experiencing pretty annoying levels of nausea recently – [...] I’m wondering if it’s at all related to the drug cocktail I’m on.

Yes, very likely. Nausea is often a symptom of you-body-goes-through-some-change-that-your-brain-can't-keep-up-with-and-that-leads-to-nausea. I guess it will pass once your transition is complete and your mind has adopted to the new body configuration.

You can look at it like hardware/software. The hardware changes, but the software is still the same. So the software doesn't keep up with the hardware, and that leads to minor bugs and inconveniences. Sensory data gets reported in a skewed way, and all that leads to nausea, which is a generic way of your brain telling you "i don't know wtf is going on".

I am ftm, but when I started trying to transition with hormones I had the same issue. I even cut weed out in hopes that was causing my nausea. Mine was so bad that I would not eat for weeks and I ended up getting a saline bag twice because I didn't want to hydrate. My endo was not as sure as your doctors that hormones couldnt cause the nausea, and when she investigated she found it's a very rare side effect. I quit t and was fine afterwards.

But, the fact you've been on hrt for so long before the nausea makes me think you have something else going on. Maybe you have an ulcer? I can see that lowering your hrt absorption. Buproprion can definitely decrease appetite, and I have taken enough mood stabilizers that I'm sure appetite loss is a common side effect. Honestly, if I were you, I'd be going to my primary care doc and trying to approach from a gastrointestinal point of view

The combination might not be causing nausea, but nausea is a potential side effect with Lamotrigine. When I was being treated for Bipolar Disorder, I had to switch mood stabilizers due to random vertigo spells. I hope it's something else if you've been feeling stable (mentally) with your current prescriptions since changing psych medications is a huge pain!

any chance you smoke weed to help with that depression? Cannabinoid hyperemesis might be worth looking into