I knopw they've got a good plan for women who breastfeed and follow SW (I hvaen't followed anything else since SW for 5 years, so no clue what the others suggest
) but we've had lots of pregnant and breastfeeding women follow SW in our groups, and their midwives, etc. have always been happy with them doing that as they've stayed healthy
It will take some time to get used to, as does any plan, but once you get into the swing of it it's pretty straight forward
Fingers crossed for your first WI, and good luck!