We went to sleep school with my DD last year. At 13 months she was sleeping usually no more an hour a night and had never come close to sleeping through. We made such progress at sleep school, I felt so confident when we left. But the first week at home was HARD! She regressed quite a bit and I thought we'd failed. But I was so determined to stick with it - so I really didn't go anywhere for the first week or so and just stuck to exactly what I had been taught. By the second week back, she was a different child! She now self-settles, sleeps well during the day and sleeps through every night from 7-7.
Remember - your bub is back to the scene of the crime, so to speak. It may take a couple of days but you will get there. You CAN do this! Be confident and consistent. Stick with it - it will work!! You just need to believe in what you were taught and believe in yourself.