Similac is fine. By enlarge you are doing great. 2-3 hourly feeds are better as newborns don't have much energy reserve in first initial months of life (lack of brown fat. Which requires frequent feeds. I would insist on keep trying for breast feeds as there is nothing superior then breast milk as it is human specific, and baby specific. High immunity provider and iincreases bonding with mom.
Secondly, well --> day time more sleep and night time more cry is a normal behavior of a newly born, that's fine. It's not a disease per se.