I have had dizzy/lightheaded feelings when I move from a crouched position to a standing position for quite some time. Now I have been having more dizzy feelings when I have been moving around. I keep my carb intake to under 50 per day, drink plenty of water and take a good multi-vitamin. Some exercise but not enough.
Has anyone else felt this and any reason why?

Sounds like some kind of vertigo. Have you had any inner ear problems in the past? Perhaps an ear infection that hasn't quite cleared up? An upper respiratory infection recently? People can also get this kind of vertigo from low blood pressure/low fluid volume. You taking any kind of diuretic that would make you lose more water than usual? Perhaps you should visit your doctor.

In the meantime, please be careful changing positions suddenly. I'd hate to hear about you in a nasty fall. And no climbing ladders!

Thanks for your support.
I did talk to the doctor and he explained that with the weight loss my body was like a balloon that was squezed at the bottom when I crouch down and when I stand it gets released. It just seemed to get worse over the last week and it might have been allergies.
I think my big problem was probably that I was losing lots of weight but not exercising regularly and now my body is not happy.

That is a lot of weight you have lost. Give your mind and psyche time to adjust to your new lighter body.

Now and again I get slightly dizzy spells - very fleeting. Exercise definitely helps. Avoiding sudden and quick movements especially rising helps too.

Congratulations. Doing great.

Take care.