Is your doc very breastfeeding friendly? It often perfectly normal for a breastfeeding baby to gain slowly, and many more things can be tried befor supplementing. My first pediatrician told me My son was gaining to slow and i needed to supplelement, i switched docs and my new one told me baby was perfectly fine. As soon as you supplement, the baby is less hungry, nurses less, and your production goes down, which creates a vicious cycle. Yes, it an be exhausting, but if you are worried about weight, just put the baby to breast as often as possible, no pacifier, no bottles, no supplements. Eat plenty, things such as oats can help. Don't freak if baby nurses constantly, this is normal sometimes! It's natures way to build supply.