Yup, totally normal.
In the normal 3 phase hair growth cycle some hair is lost every day, although you won't always notice it because at the same time, new hairs are growing and some hairs are resting. (That's why when you shave or wax your legs, you'll see the odd hair appear within a day or so because those little hairs are at the peak of their growth cycle.)
However, during pregnancy the increased levels of oestrogen in your body keeps the majority of your hair in the growth phase of the cycle. Hair that would normally fall out stays put, resulting in lush thicker hair.
At some point after giving birth, your hormones start to revert to their pre-pregnancy cycle and all of the hair that would have naturally fallen out slowly during the whole of your pregnancy start to fall out at that point. So it becomes far more noticeable and obviously, your hair will feel thinner but it should start to settle back into the normal hair cycle within about 3 months or so depending on your hormone levels.
With some women, the hairline appears to recede during this phase, which can seem scary, but this is entirely normal. You should start to see the new baby hairs growing within about 2-3 months.
Your little girl looks gorgeous, by the way.
