I'm a 30yof. I've been getting dizzy spells and blurred vision. Just really tired spells too. What could cause this and I'm 35lbs overweight.?

See doc right away. Dizzy spells, especially when they are associated with any visual changes needs immediate evaluation; in addition you are having tired spells. There are a number of disorders that could be in the differential diagnosis, but the one I would be most concerned with is an inflammation in arteries in the brain/scalp area, specifically temporal or cranial arteritis/vasculitis. Go, get a sed rate done.
Low blood pressure. It sounds like you are having some low blood pressure. Orthostatic hypotenion--low BP on being upright, especially quickly. Also, significant anemia can do this as well. I am not sure if you are taking any meds, but some meds can do this too. Keep yourself well hydrated at all time. Take it easy getting up/dow--do it slowly. If symptoms not better or worsen, consult your doc for eval. Good luck.