Make your golf game more pleasurable by buying an electric golf trolley.  Once purchased a golf trolley will benefit your game by allowing you to keep your concentration on the game without feeling exhausted.  When your energy levels are down it is often due to lack of energy due to dehydration or food levels.  If this is occurring more often then it would be advisable to get yourself fitter. 

Having an electric golf trolley is fine, but try not to use it for every game. I would advice to carry the clubs when not playing a competition, then use the electric golf trolley for the competition only.  This will adapt your body's conditioning to expect a golf round to be more difficult, thus when plying with the golf trolley it becomes easier and therefore you last the whole round without a problem. 

Well that's my theory, hope it works for you.