Yep, this is known as dp/dr (depersonalisation and derealisation).
It often goes hand in hand with hppd visual symptoms. It's my most hated symptom. The feeling of being on a boat is also connected to this, imho. We do not feel 100% connected to our body and it puts us off balance. Even the smallest head movement can make me feel disconnected.
I've always maintained that what people often refer to as hppd is actually 3-4 issues in one. Hppd visuals, anxiety, dp/dr and sometimes depression. Clonazepam is the only thing that helps me reduce these symptoms.