Becoming A Medium

I have recently lost my son. He was murdered. I met with a psychic and she told me he hasn't crossed over yet. She said that he had told her he would let her know by the end of the day if he was going to. But that he wanted to be present for the reading. I believe what she told me. She validated some things that only my son would know. She said I should pray for him to go to the light or to God. I have done this. She also did a tarot card reading with me. She said a prayer and asked that my son choose the cards. Medium was one of the cards. She said he wanted me to gain the knowledge to do this so I could communicate with him. Just want to know where to obtain the information to begin with my journey, I do believe he is trying to communicate with me. I have captured 2 pics of him on my camera since he's passed. Would love some guidance here.

This is all new to me. I miss him so much. Sometimes I can swear he's talking to me. Do not like thinking I'm going crazy here. Any help would be great. Is there any workshops available or books. I don't have too many people in my life to talk about this with. I was at his grave the day after the reading and I asked him to give me a sign if this was real. And the only way I can describe it is that when I looked out my car window toward his grave it was like looking through glitter. I rubbed my eyes and looked out the front and the passenger window and the glitter effect was only out drivers side where I was. I could even put my hand through it. This lasted for about 5 minutes and then stopped. I know this sounds crazy. Has anyone else experienced anything like this?