You're wise to be cautious; cults can be very aggressive in trying to persuade people that they -- and they alone -- are right. Often they stress one particular theme or doctrine, claiming that they alone know what the truth is about it.
A cult is a religious group that rejects what the Bible says, and denies what Christians have always believed. Some cults reject the Bible totally, or put the teachings of their founder on the same level as the Bible. Others claim to believe the Bible -- but in reality they reject what it says about Jesus, or salvation, or some other important truth. Often cults are led by a strong leader who demands total loyalty.
I sense from your letter that you have a hunger in your heart to know God -- and that's good. Don't be led astray, however, but turn to Jesus Christ and ask Him to come into your heart and life. Jesus' promise is for you: "Ask and it will be given to you; seek and you will find; knock and the door will be opened to you" (Matthew 7:7).