Honestly my roughest dose was the very first one. Didn't feel anything right away, but within a day I had a brutal headache and felt nauseous. Figured out that drinking a ton of water made a real difference. Also picked up some ginger candies that ended up being key for settling my stomach. Never actually thrown up, but what I've dealt with leans more toward heartburn, indigestion, and constipation, all things I've learned to keep in check through hydration, enough fiber, and better meal timing (steering clear of big dinners late at night).
Currently on the highest dose, and side effects are pretty much gone at this point. They stopped being noticeable right around when I moved up to the second-to-last dose level. All this to say, these reactions are completely normal and manageable, and eventually your body adapts and they fade. Just remember to drink plenty, never stop eating entirely (for me at least, hunger would actually show up disguised as nausea), keep meals balanced with enough protein, and keep portions modest. Hope that helps!