Hair falling out while feeding?

I have been feeding my son almost 6 months now (I fed my daughter 2 and a half months before she stopped and I didn't have this issue) and im starting to go bald! My hair is falling out in huge clumps and im worried it wont grow back. I have a feeling it is due to malnutrition, we do not have a lot of money so I eat what I can. I have however started taking my prenatal vitamins 2 days ago. Did I start taking them too late? How much longer do I have to suffer hair loss, and will it grow back? Any other suggestions on whats causing my hair to fall out and how to get it back?