You just got home. Your breasts are hard, hot, heavy, and maybe even a little terrifying. This is engorgement, and while it feels like something is wrong, it's actually a sign that your body is doing exactly what it's supposed to do.
Your body got the signal to produce milk and responded enthusiastically – maybe a little too enthusiastically. The goal right now is just to keep feeding your baby on demand. Your boobs may feel full but milk production is still ramping up. This stage (engorgement) is what happens right before your body produces loads of milk.