Hello Nicky, Welcome to Minimins. For the first few days I had a couple of afternoons when I came over very lightheaded , felt a sick sick and suddenly felt very hot. These stoped after about 3 days. My LLC advised splitting the packs and having six "meals" a day until it went.
Also are you drinking enough water, that always seems to be the first question but it definitely helps.
Just take each day at a time and if you are worried call your LLC.