both my kids had breastmilk jaundice (something in my breast milk apparently).
My kids had really low levels so my ped wasn't concerned and I didn't switch to formula but agreed that if DD or DS had it after her 3 month appointment I would switch to formula for 24 hours then back to bfing. I think with DD it cleared up by her 3 month check up and DS was 2 months...I think.
My kids had really bad colic and reflux (DD was worse than DS) so my ped told me if we switched to formula we could expect the colic & reflux to be much much worse so we wanted to keep them only on breast milk, mylicon, and Zantac and only do if I "had to".
Point is you don't have to go on formula if the levels are low. They will outgrow it!