187.6 (6:30am) full carb, exercise water retention

In Oregon right now. Ate potatoes and cake last night. Walked about a mile and a half yesterday morning and the previous day. My muscles feel sore, so hopefully a lot of this is water retention. Either way, setting this weight this morning scared me. I a interview for a job in six more days. I don't know if I am supposed to be under 32 or 30 BMI. Either way, I'll get under 30. Just wish this wasn't a recurring theme. DH is down to 195, I need to get my act together.