Bad stomach/diarrhoea early pregnancy

I just found out I’m pregnant, 3-4 weeks. I’ve had IBS for years so am used to going to the toilet frequently. But this week I’ve had diarrhoea in the mornings. I usually go 2-3 times across the day. I’m meant to be going to my partner’s family house for a few days and it’s not ideal to have diarrhoea there, also no one will know I’m pregnant. Anyone have any tips? I won’t be able to do BRAT diet as I’ll be eating Christmas food