I just had a baby via c-section 4 weeks and I feel vry dizzy and lightheaded and I'm having headaches

Congrats on the new baby! Are you eating well and often throughout the day? What is your fluid intake like... are you taking in plenty of fluids? Do you notice it more when you change position or is it more constant?

Since you had the recent surgery, it would be wise to give your doctor a call.