First day after first shot

I just switched to Mounjaro from Ozempic because of the terrible side effects. Are there different strengths or do you just take the whole thing at once and it lasts a week? I’m feeling pretty nauseous and was surprised that directions didn’t give options for different strengths - am wondering if this is why on the second day I’m feeling really nauseous.

The dose was 2.5 mg. Once per week.