As the fellow above hinted at (I think), sometimes we go in cycles like this. Just relax, study what intrigues you, continue with your meditations, etc. Calmly explore the nature of why you can't sense the energies and spirits and so forth any more. Consider if there is an imbalance in your life. Is there something that leaves you feeling uneasy?
Etc. You'll work through it.
As to how long it takes, that will vary for every individual.