You should not be donating blood at this time because it will not really benefit anyone, it will be lacking in iron and B12 and the doctor will just be more confused about why the patient is not recovering.

I have not heard of nausea as a side effect of low B12 or iron. I would think that your nausea comes from something else. For example, perhaps your stomach is bloated and you really need to burp. Or, perhaps you are actually having a migraine, especially if the pain is behind your left eye, and feeling nauseous and vomiting is common, and would be expected especially since your hormone levels and vitamin levels are so terrible.

It could also be heat exhaustion or dehydration are common.

If your tummy has been upset or hurting when it is empty, or if you've been having a lot of acid reflux, please talk to your doctor about h-pylori.