Is this pppd?

So, I am having these symptoms when I walk in the store and look straight. It feels like the stuff in front of me is moving up and down. It's very hard to explain. I know a lot of people say 'trampoline walking.' What does that mean? Also, my leg feels weird while walking, like it's not attached to my body. I only feel this while walking; when I sit down, I don’t feel anything. It is not dizziness but a weird sensation. I had a clear brain CT and MRI, only sinus inflammation. Please share how you feel with Pppd