The six realms of existence
If you are worried that your current karmic existence is, or is related to, that of a hungry ghost you should apply the proper antidote. In this case the proper antidote is practicing/developing the first paramita : generosity  Doing such and being aware of your desires and the desires of others can help curb the feeling of constantly searching for some unknown thing. 

As for how to know if your efforts are proper, or for good as you say, I'll turn you to the short and sweet lojung saying "Of the two witnesses, hold the principle one.

Try these things and meditate on them, see if they help, I hope they do. Remember, we all exist in this confusion together, you are not alone in this.