This could be related to a lack of energy. It could also relate to being too close to your physical body. There is a strong reactionary field around your physical body, strongest within 20ft (6 metres). Moving away from your carbon body will help with this.

The tired eye sensation could possibly relate to developmental changes occuring in your brow center. If so, this will eventually rectify itself.

Apart from energy work before projecting, a strong command during OBE will help. Command 'Energy NOW!' when you feel tired. Your higher self is much closer to you during OBE and it should thus respond and give you more energy.

Robert Bruce