The suppression does lessen as the week goes on. That's normal. It has a half life of 5 days so after 5 days half the dose has left your body.
I have been taking Mounjaro for 7 months and am currently on 15mg. I still eat more on days 6 and 7 each week.
I scrolled back and saw you say you lost a stone on pen 1. That's a big loss although I don't know your starting weight. You seem quite sensitive to the drug so would probably still lose weight on 2.5mg with less side effects. (By comparison I lost only 7lbs on my first pen and have had no burps, V&D or anything else till I got to 15mg and even then it's just nausea and over strong suppression for 4 days so I am not a super responder at all. I don't take 15 every week as the cumulative effects are too strong and make me too tired to live)
You need to drop back to 2.5mg and either stay there or increase very slowly so you don't feel as ill again as you do this week.