Re: less at night
What you describe is absolutely normal. Most moms have a dip in supply at the end of the day, and at 12 weeks, most babies want to be at the breast all the time, particularly right before bed when they are tired and hungry and cranky and want to tank up for their first significant stretch of sleep. The best thing you can do is to not resort to the bottle, and just nurse, nurse, nurse. This will train your body to produce more milk in the evening, when your baby requires it. Every time you offer the bottle, the baby skips the nursing marathon she was otherwise going to give you, and that means your body misses the message that a nursathon gives, which is "Make more milk!"
As long as you continue to nurse on demand, you will not run dry or need to supplement.
Congratulations on making it to 12 weeks! You've gotten through the hardest part. If you can do 12 weeks, you can do 12 months!
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"