Thanks for following up with an update Helenmaree, and for creating this post. It's always good to read similar experiences.
I'm going through a period of lightheadedness/woozyness myself at the moment too.
I've had this a long time (20 years) ago when I was younger, and was having some health anxiety (and of course it turned out to be nothing cause I'm still here).
Last year I started having some health anxiety again, and this time at least I recognized the feeling of lightheadedness. I could even find some old notes from way back to make me reflect on how this feeling is similar to then.
And since about 2 weeks, it's started again unfortunately. A bit stronger and more persistent than in the past.
Like some of you on here say, it's hard to describe. I would say feeling "off-balance", lightheaded, woozy, with a hint of headache/pressure in the background. I also find that from time to time it's like a 'jolt' going through my brain.
PS My stressful background is that I've got a 6 month old baby, so sleep is not always as much as I need it to be, and the pressure of responsibility is subconsciously weighing on me. Also the fact that my (/our) days are pretty much scheduled now, which is much different from just do whatever you feel like outside of work hours.
Sorry for the ramble, just had to get this off of my chest.