I really hope not 
DS1 has been BF since birth, with 1 bottle of formula before bed (I'd pump while DH would feed). Last week I had a bit of a scare with a burst blood vessel, which resulted in DS posseting blood and a quick visit to A&E.
I was advised to give my breasts a break for a day or 2, and so gave him formula for 24hrs, while expressing to prevent engorgement or mastitis. I started BF again the next evening and things seem to be fine.
However, I have noticed the last couple of days that my right breast supply has gone right down - as in only getting