CHICLET! Please just stop with the lactation consultant!!!!!!!!!!!!!!!!!!!! You just said it - "I think it's the LC who has me stressed out" While LCs are great, and serve a purpose, they are also VERY single minded "BF is best, only BF, pump so you get all the BF, BF BF BF!" But a stressed mother is not a happy one, and a baby needs a happy, UNSTRESSED mother. It will be stressful enough to go back to work, please don't add to it by letting that LC stress you!!!!!!!! If your DOCTOR (you know, 7 years of med school, blah blah) isn't worried then try not to. You are going to have to give something to childcare to feed the baby - will that be formula or BM? If formula, you could start the transition now so baby is used to the taste of formula (although many babies switch back and forth between BM and formula without a problem - they figure, if it's in a bottle, it's for me!)
Seriously, ENJOY the last three weeks with baby chiclet, you'll never get another family leave with this baby. go outside, take a walk, feed when baby seems hungry, or if it makes you feel better, feed him every 3 hours, but just nurse him and enjoy it. You said you're enjoying the nursing, so do it, but take the pressure off.
I think you should just skip that next lactation meeting with all the weigh ins, etc. Weigh in at the doctor's office only, and relax. Look, if your baby doesn't continue to grow on his growth curve, the doctor will get upset soon enough and you'll do whatever he tells you to do - we had one tiny baby who had formula added to his breastmilk on doctor's advice to gain weight. And he did, and that's great, but he's also very busy and active - at 18 months he eats well, loves food, but doesn't walk if he can run. And he's still small and little and petite, and probably always going to be that way, but he's healthy as a horse.