Voices From Loved Ones?

Recently, I've been wanting to contact my Grandmother that passed a few years ago. When I wanted to contact her, I focused on her and said a "Hi, I love you" thing. When I did that, I got a reply in my head. Not only that, but she told me (still in my head) to tell the rest of my family that she loves and misses them. After that, I got a 'vision' if you would of her giving a giant kiss to my dad. Ever since I have had that 'experience', I have been tempted to ask people if they have had any loved ones that passed. For example, I will be at school and I will walk by someone and automatically know who has passed (Example, an aunt) and I am 'tempted' to give them 'messages' from that loved one. Not only do I automatically know, I will sense their loved ones presence. I have sensed some that aren't at rest, negative, and I have sensed good spirits. Example the other day, I knew this kid who's father passed away of a Heart Attack. Whenever I saw him, I sensed his father coming to me to tell him that he is sorry he passed so early. I also felt that the kids fathers soul isn't at rest and I also felt he was depressed/sad. The other day, I felt 4 spirits total in a day to give someone a message. All of them were my friends. One of them was my friends grandmother that passed and I felt negative and that she wasn't at peace. I asked her (I knew she would understand because she is Psychic and practices witchcraft) and she said that she thinks her grandmother isn't at rest either. I told her what was going on and she thinks I am a medium?

The other day, all the times I felt a spirit presence wanting me to tell someone a message, I asked that person if they had that that family member that passed (that I felt in the first place) and all of them were the ones that I felt (meaning I got validation that I did sense their presence) And then once I got validation, I told them what their family member wanted me to tell them.

What is all of this called and why is this all happening?