Hi M. T,
I always shed a TON of the baby weight right after delivery but by about the 3 month mark i start gaining some back, though usually not more than about 7-8 lbs. (it adds up after 4 kids though!!). I am actually trying to change my metabolism because I'm gaining though I wasn't eating enough to justify the gain. I make pretty good food choices too. I don't have time to workout either, though I'm trying to use my kids as weights and resistance to help tone things up a bit :) my son loves airplane time and my thighs are getting a good workout at the same time!
I've been taking a multivitamin, and eating 6 small meals throughout the day to help boost my metabolism. I read small meals are supposed to help... starving yourself actually has an opposite effect (even if you're not doing it on purpose) and causes you to store your food as fat for use during those famines.
Also, building a little muscle is supposed to help burn fat faster - by no means do i plan on becoming a weight lifter but, strength training is a good way to build muscle. I use a 5 lb dumbell - not trying to be the Terminator, but I'd like just my hand to wiggle when I wave :)
Anyway, that's about all the tips I can give... besides taking the stairs when possible, eating fresh fruits and veggies at 4 of my 6 meals, balancing it with whole grains, lean meats and few carbs (you do NEED carbs - and you will crave them something FIERCE if you try to eliminate altogether). And as a treat, buy a king size candy bar, cut it into 7 equal pieces - pop it in the freezer and have one piece every day - that's my huge thing - i cannot eliminate sweets - i love cookies, cake, brownies, etc. I get a Snickers bar and get all my yummy's in one bite and I don't feel like i'm being deprived of anything!
Another thing I've done - stop using your dinner plates - I use a luncheon plate at dinner and it helps tremendously to keep me in check for portion controlling. If i go for seconds, I only let myself have more veggies.
I am also doing this for my daughter who is 12... she is having issues with portion control and tends to be a bit glutenous about food and is making poor choices. She see's food as rewarding, so on another note, don't use food as a reward for your child(ren), ever. I am finding way too late that it sets them up to have an unhealthy relationship with food.
Good luck on those last 20 - you've come SO FAR!! pat yourself on the back Momma :) And congrats on your new baby :)
p.s. I cannot give any advice on the period issue - I have never been a successful breastfeeder - kudos to you on that :)