My 5 year old started hitting kids in kindergarten

My 5 year old started kindergarten this year and recently has been hitting other kids in his class.  He has also hit me when he gets very frustrated.  I have told him how he needs to use his words and never his hands  He sometimes cries that I am the worst Mom ever and that everyone hates him.  I have tried timeouts, taking away his tv, taking away toys, desserts, etc.   I tell him that we love him, but he cannot act like this.  I am at my wits end as to what to do with him.  I don't know what to do to make him stop this behavior before he hits someone hard enough to actually hurt.