thank you for breastfeeding!!
what you need to do is get in contact with a local or nearby la leche league group or leader.
your doctor is giving you poor information. the nighttime feed is NOT unneccesary. there is no such thing as she "should" go all night. your child is who she is, and she has her own needs. my son was one of those "high needs" babies. nothing wrong with him, he just demanded and required more than laid back babies. he would not accept substitutes. he nursed until he self weaned at 20 months, and we had him sleeping in the same room as us, usually in his crib but we did our fair share of bedsharing as well. he nursed at night until between 15-17 months.
fact of the matter is that her tummy is TINY and shes doing a LOT of growing! babies triple their weight in the first year. now, that actual amont of weight might not seem like a whole lot to you, but you try tripling your weight in a year; you will have to eat a lot and often! this also helps reduce the risk of SIDS because she is waking so often
the 4 am feeding is not habit; its something she needs. her tummy is empty. shes just going to lie there and scream and figure out you wont respond to her if you go that route. not exactly a trust building exersize.
so get ahold of a local la leche league leader. you will not regret it. look up information on their website; www.llli.org. also another good resource is www.askdrsears.com.
this is normal, more common than we think, and its horrible that doctors are giving the impression that babies should sleep perfectly through the night at such a young age. fact is that babies dont and shouldnt sleep like adults. and if you think about it, how many adults do you know that sleep all night? how many times do you get up and go to the bathroom, get a drink, or turn over and get comfortable at night? chances are you wake up just as often as she does.
bedsharing might help. contrary to the general public's ideas, its safer than you think, and you both will get a lot more sleep. you have to be ultra aware of the blankets and pillows on your bed, make sure that nothing gets in her face. when i did it, i was always very aware of where my son was on the bed, where the pillow was, blankets, etc. i never had a problem. and i got so much sleep!!
anyway, i want to encourage you and tell you that you are doing the right thing, and you are doing just fine. follow your instincts, throw the doctors information out the window (obviously the doc either doesnt support breastfeeding, doesnt know enough about it, or didnt do it themselves...)
la leche leauge leaders have breastfed their babies for at LEAST a year (usually longer) and they will have information that will be so helpful in your breastfeeding journey. trust me, you will NOT regret listening to the advice and information they will have for you. and trust yourself. you know what your child really needs deep down inside, its you, your milk, and your love and trust and all of that. she doesnt "need" to sleep through the night, she doesnt "need" to wean, and she doesnt "need" to be "perfect". she just needs to be who she is with her own needs and stuff. :) and thats going to ensure that your little girl grows up to be the best happiest she can possibly be