My husband and I call this "my own personal earthquakes". I wobble, he looks alarmed, I reach out for a wall or furniture, or just do the "startle arms" like an infant, or if he's close, he grabs me, and we go "Did you feel that? Earthquake!" and laugh. Or "Darned walls/floor/etc won't stay still!".

Having a cold or allergies can definitely kick things up, the increased pressure and irritation will magnify something you may not have realized was still there. Also, it may be worth having a doctor take a good look at your ears, if even a minor infection has settled in it could be doing this to you. I went through 7 months of room-spinning dizziness when I turned my head in certain ways because it was just assumed it was from the accident, but it was cured (gone!) accidentally when I was put on amoxicillin for something else. (Curses on every doctor who never took a good look during those 7 months!)

Unfortunately, my permanent low-level dizziness which was pre-existing, is still here. So my personal earthquakes continue.