Ok I really want to lose weight and I'm willing to exercise but everything I do makes me really dizzy... like walking sometimes and sit-up etc and I have no idea what could cause it does anyone know what this could mean:confused:

Sounds like a circulation issue. Are your fingers or feet chilly often?
It is good that you want to exercise, the more that you do (carefully) the better your circulation will become in time. Before that though, you might go to the doctor and make sure your blood pressure is normal. Make sure you are eating healthy and try to take baths before you go to sleep.

Here is a link to some simple exercises that will improve circulation. Deep Vein Thrombosis, 5 Exercises for Improving Circulation -- RealAge Health Information
I recommend taking yoga as well -- after a couple years of taking it I was very pleased as it toned my body, improved my circulation, and kept me flexible. This is a good step to losing weight if exercise is new in your routine, paired with 30 minutes of walking.

For exercise, I have to suggest you, just consult with online fitness provide sites.