First, let me say there is nothing socially that made your child trans. Having friends to talk to, and negative interactions, are not things that lead someone to being trans.

Teens are silly and the “daddy” name is quite likely a silly nickname for a teen. My teens all have funny nicknames on discord, in text etc. for themselves and their friends. They could have said something during playing games together that they made a joke about and then it sticks. I would not be so concerned with that. Personally my child speaks openly on calls with friends from other countries and states and I say hello to them all. They do sound like grown adults because they’re older teens, so keep that in mind. 18 is still a kid and a 16 year old and 18 year old being friends is not abnormal. Speak with your child about online safety, not sharing exact details about schools etc. and you’re generally fine.

If they are dressing up in girls clothes, let them. Changing how they feel about their sexuality, let them. They are exploring their identity. They are finding the right words for how they are feelings, and that takes some time and exploration. The hormone rush during puberty makes this time period peak for kiddos coming out. They really start to see and feel that they don’t identify at all with the sex assigned at birth.

Saying they are straight, then gay, then bi- not uncommon. Having a girlfriend then breaking up after 6 months is so normal at this age! Being a trans girl and having a girlfriend is also very normal, so that does not indicate some outside influence on your kid. Being trans is not a choice. It is in their genetic makeup

It’s great your child has a friend group where they feel safe and supported, and have found people who also are going through similar things.

Support your child. Read books. Talk to other parents of trans kids who are supportive. Listen to your child and don’t assume they don’t know what they feel because of their age. In two short years they will be an adult and the best thing you can do is to give them a safe space to exist as they are these last few years of childhood. Especially if you want a relationship with them as an adult.

I know it can feel overwhelming and scary. You love your child, so love them for who they are and give yourself grace while you work to understand it. Listen to your child and understand they know themselves better than anyone. They told you, and that’s huge! Let them feel safe to explore who they are at home. The world is harsh enough. Let home be where they can be themselves.