bilingual kids

i am an Indian mom and my son is 2.6 years old. We speak both Hindi and English at home. We try to speak English more but sometimes Hindi comes up. We are not as fluent as advanced speakers or natives. I am worried for my son. He can speak 2 words at a time but he is not forming sentences. Can any of you also have the same experience? Should we use only one language? how can I help my son in this regard particularly when he doesn't show interest in listening. he is just naughty and want to jump around