Hi you can take multivitamins, but, remember masturbation does not deplete your energy. Your feeling of exhaustion or loss of energy may be due to the neuromuscular mechanisms involved in orgasming. You will feel the same exhaustion in intercourse too,but people tend to think it is normal. If the same happens in masturbation they are worried that masturbation is depleting energy. In both situations, having a good sleep or even a nap after masturbation/intercourse will make you energetic.