We've been trying for the 7 AM wake up since day 1. And if I feed at a 6AM eu I'll try to put her back to bed until 7 and nurse again
I did the same thing:) Any waking before 7 was a NW for me and DH would offer her a bottle and put her back down. I must mention though -- Once I started a fixed WU time of 7, in a day or two she stopped waking for that 5.30/6 feed. I think she knew it was coming. If she woke early, I would let her chat and play around in her crib and only go in at 7.
She only slept 8.5 hours last night then nursed for 20minutes at 430AM. Could some of this be due to low milk supply?
Not at all. It is completely normal for babies to wake up to eat at night. They need the calories. And 7 to 4.30 is a great stretch. The DF really worked for us in this respect. It eliminated the 3.30 feed. You mention it causing more WUs - how long did you try? The first day we tried, DD was very unsettled but we persevered and it was great. I did and do not nurse for DF or NFs though. DH offers a bottle.
My supply has dropped since she started the long stretches of sleep at night. If I pump at 6PM I get an ounce max from both sides combined.
I wouldn't think of it as 'dropped' but rather as adjusted to her needs. You know, after DD started sleeping through, for the longest time I would WU ay 3.30 and pump because I was sure my supply would disappear:p Very silly of me. So don't worry - you have as much as she needs. When you say you only get 1 oz at 6 pm, is that after feeding her? I found that I get the most first thing in the morning and before going to bed at night. So when DD started sleeping through, till now, I pump before going to sleep at night. And after she started STTN, she would only feed from one side in the morning, so I would pump the other. A pump is not a good way of estimating your supply. Baby is much more efficient at getting out the milk, and as I said, your body will produce what she needs. Just keep nursing regularly