Old fashioned smelling salts, or lemon or peppermint essential oil However if it keeps happening it may be post viral fatigue, did you have Covid recently, or could you have had it without realising/testing.
Vit D deficiency can cause fatigue too, a simple blood test could eliminate that as a possibility.
Nothing wrong with a little bit of caffeine, maybe just have normal tea or coffee when you need to be alert. You won't need to guzzle the stuff if you are not a regular drinker of it.
I avoid energy drinks Pepsi max is my caffeine hit of choice but even that I ration these days.