Sleeping through the night

Vanessa • Married to the most wonderful & handsome man in the world! 👧🏻💞 born Oct. 23. 2016 & 👶🏽💚 born May 2. 2018 ♥️IG: DwyerBearFamily
I announced too early on social media that our baby girl was sleeping through the night and feel so embarrassed lol no one knows yet and I think only a few close friends will find out when I see them. I made a cute picture announcement too 😂 omg. I believe it was just her growth spurt those two or three days she slept through the night 😩
Anyways!
How do we get our little one to sleep through the night? My baby girl already takes small cat naps throughout the day although her biggest nap is 3 hours in the morning. I try and feed her good amounts of milk throughout the day (formula fed) I have it pretty dark in the room when bedtime comes around and completely shut off all the lights by the time she knocks out. She currently goes to sleep at 9 or 10pm and wakes up at 2 or 3am and than goes to sleep and doesn't wake up again until anywhere between 6am to 8am. Help! I'm supposed to go back to work and my husband and I could really use the sleeping through the night in the next two weeks. She will also be 3 months old on 1-23-17
Thank you!