It can only be a guess long distance like this, but I would suspect that there is a poor connect from wherever the power is coming from - likely another bedroom. Check to see if there is power anywhere on any of the switches. If not, open the light fixture boxes (probably have to remove the fixtures) and check there. If you find power anywhere, try and figure out how it gets to the switches and make sure there is no bad connections.
If you don't find any power anywhere it means either the breaker is tripped or that it has been lost in another room. Repeat the process for any other switches or fixtures anywhere on that circuit.