I'm 40 years old, i felt dizzy everytime

I'm from the philippines and i feel dizzy and light headed when go in my backyard and im not the one, my brother too feel the same thing whether just digging for planting or sweeping leaves or by just resting there i feel my body shaking and my knee felt weak, we moved here just a couple of years ago, the surroundings was full of tree and a creek, I don't bother at first but when my brother told me he felt dizzy when visiting here my doubt builds up to this extent