I work in the sun all day. time i get home i feel drained. bit light headed. tired. & little headache. seggestions?

It's expected. : Your likely dehydrating yourself despite thinking your drinking enough water. The sun will fatigue you on part due to dehydration and in part to damaging your skin which requires a lot of your body's energy to heal. Remember your skin is your largest organ. Stay hydrated (best to drink water) use SPF and wear a hat and wouldn't hurt to eat a couple of saltines to maintain salt and carbs.

Pace yourself: You say you work in the sun all day. Do you mean to say that it is a hot environment & you sweat a lot? You may be suffering from heat exhaustion although the "exhaustion" part may be slightly exaggerated. Exertion in a hot environment will cause anyone to feel tired, drained, and lightheaded. Pace yourself with more breaks. Hydrate every 20-30 minutes with cool water. Eat salty snacks.

Dehydration : It sounds like you maybe suffering from mild dehydration and possibly mild heat exhaustion . It is up to you to replace the fluids list while you are out in the sun . You need to during at least 64 OZ if electrolyte containing fluids such as gator aid while you are outside . This will help keep your BP up and hopefully keep u from being exhausted . Take care .