How much does your baby sleep??

Nia • Currently have an almost 2 year old, and newborn and 3 angel babies ❤❤❤💗💗
My daughter is 12 weeks today and the most she's ever slept at night is 6 hours straight and I can count those nights on one hand. I'm so exhausted and going back to work soon. Just wondering how much other March babies are sleeping at night? And if anyone has any pointers or tips to get baby to sleep more at night?