Post Partum Depression Support Group
Postpartum depression (also postnatal depression) is a form of major depression which can affect women, and less frequently men, after childbirth. It is widely considered to be treatable. Studies report prevalence rates from 5% to 25%, but methodological differences among the studies make the actual prevalence rate unclear.

Your dizziness/lightheadedness could be due to a sinus infection or allergies. Have you experienced this in the past? You cannot rule out anxiety in this case. Everyone has different physical symptoms that can accompany this.
Please don't feel like you are crazy and creating this in your head. PPA is very real and quite common. It might help to find another Dr./OB to discuss this with.
Hang in there - it can and will get better!
The dizziness could be sinus (I get it too.) It could also be a panic/anxiety attack. I also get those. They do feel quite different to each other. I know when I'm having a panic attack because my respiration rate doubles.
You may need anti-anxiety meds or maybe just to do some breathing exercises. You need to alk to your doc or another one if your doc isn't taking you seriously.
Cath