Don't worry. Usually I can cope with ds1 (severely autiistic- 6 year old) and the other 2 (3 and 7 months) but last week in a campervan I absolutely could not cope wiith the pressure of ds1 in particular. And I screamed and swore and shouted at dh all wek (and he did the same back). It'll get back to normal and you'll be able to do that swithc off thing you have to.
DS3 spent a lot of time in a sling whilst I was chasing ds1 otherwise he was just crying, and I couldn't deal with him and ds1. Don't worry it gets better
Oh god doon;t get moondog going on milupa