Yes, you definitely need a lot of liquid while breastfeeding. Don’t ignore your thirst!
When did you start refeeding and how long had you been breastfeeding? What was your diet and exercise like before and did you have any problems w/ BFing?
Post-partum thyroid problems are realllly common, and low temps can be a sign of low thyroid function. Unfortunately, I don’t know much about re-feeding and all of the nuances about it.