Why im getting nauses again?

I'm about to turn 24 wks pregnant on tuesday, and last night i started getting nauses again just like when i was in my 1st trimester. i feel like i want to puke but i can't. i feel very bad. i feel like i have to energy sometimes then i just get really hot and i start feeling very uncomtrable. i dont know what im felling. my baby have been moving and kicking alot today.