according to huygens principle every secondary wavelet have same energy, frequency and wavelength but if we consider more wavelets originating from secondary tertiary and so on then energy of the wave will never get over and new waves will be formed continously ? how is this possible

Energy is not being created. Energy just flows in form of wavelets so whenever you consider a wavelet, remember energy in it has come from previous wavelet which is no more. But as generally sources of energy we consider are continously radiating energy so wavlets are also continuously formed and transfer their energy in all directions continuously