I had a dream I was hugging my crush at a water park then I jump off of hi and go down a slide then I go see my dads gf and the water park dissapears.
it seems to me like the water park could be symbolizing good times, probably with your crush, considering that she was there. Do you not like your dad's girlfriend that much? It seems like when she came the happiness left.
that makes sense, maybe some anger towards your dad for dating someone or something like that. maybe it feels right that you date but it feels wrong that he does