My dd is no 13 weeks and is going through a growth spurt (I assume)previously she was waking once in the night now it is at 11, 1am, 3am, 5am, 6 and 7. This has been ongoing for last 4 nights. At present she is 100% breast fed, if I introduce formula now will it mean she goes for longer (as I am exhausted) or should I ride it out? Suggestions welcome please.