Help help help help

Guys there is alot of pressure, torture and stress here in my work. My manager accepts all the work from his manager and dumping me everything. I am provided with 2 applications. But my manager accepts other applications and he will give me work in development. For IT Application owner tasks of the concerned person is on leave, he will dump me work. Apart from this i need to take interviews for new candidates also. Other managers works also. He will accept and provide me. By which I am working almost 12 to 14 hours a day. After workin so much I got good performance stating i didn't do courses itseems. Previously i had received excellent performance. To live job there are EMI's responsibilities. Also I am paid very less 7.5 lpa for 6.2 years of experience. Just because of 90 days notice period. I am not getting calls properly. Need help. Don't understand what to do.