I breastfed my twins for 6 months. I am not a huge fan of breastfeeding. I started it because my husband asked me to do it. Afterall, they are his kids too. So I gave it a week, then a month, and it turned into 6 months. I supplemented with formula when I wasn't in the mood to breastfeed. For me, I found bottle feeding with formula was faster and easier. I started to ween the twins from 8 breast-feedings/day at 4 months down to 7 feedings/day a week later and so forth. (each week I cut one breastfeeding session)
I found the first 2 weeks to be the toughest breastfeeding. I stuck with it and was glad I did. Breastfeeding made me VERY hungry. I ate 5 meals a day, plus snacks. I was constantly eating and that kept my weight stable. (I gained 30lbs with twins and lost 35 lbs w/in 5 days of delivery, but stayed there, stable at 108lbs without really trying. I just ate when I was hungry)
I'm not a fan of co-sleeping so I always put the babies back in bed after breastfeeding. Actually my daughter preferred to be swaddled tight and put in her swing for the first six months, so that's what worked for us. My son was in his crib from day 1. I found formula to "stick with them" longer than breastmilk, so I usually "topped" them off with formula at my last feeding of the night. I think sleeping through the night is different from baby to baby. My son started a 6-7 hour stretch at 9 weeks, and my daughter follwed at 12 weeks (she was MUCH smaller and I found this 10 lbs mark to be significant for sleeping through the night) I did have to pump a lot for my daughter, as I wanted her to have breast milk, but she wouldn't latch on for the first 11 weeks, but we kept at it and she eventually became a pro!
In the end, there's nothing wrong with exclusive breastfeeding (CF mom or not), there's nothing wrong with breastfeeding/formula feeding mixture, and there's nothing wrong with exclusive formula feeding. You have to do what you're comfortable with. You have to do what keeps you sane. You have to do what keeps you healthy. As long as baby eats and gains, you're doing everything right!
My doctors never discouraged me from breastfeeding. I never "pumped and dumped" because I didn't take any questionable IV meds or oral meds that warranted that. I took all the regular CF meds, including osteoperosis meds while BF'ing. My dietician was more worried about my weight and calorie intake than I was. I wasn't losing weight and felt great. I would say, if you really want to try it, GO FOR IT! And if you hate it, try and stick with it for 4-6 weeks minimum. It changes after that point. I had a love/hate relationship with it for the first month or so. My opinion on it changed everyday, or every hour. LOL! Good luck!