Advice! What to Eat After Bloodwork

Hi! Just wondering if anyone has some suggestions about how best to eat to help the body recover from blood loss. I have to get some routine bloodwork done on the weekend and I'm wondering if my body needs more calories to rebound and reproduce lost blood, or if there are types of food that are more advantageous than others. The reason I ask this question is because I am underweight, have extremely low blood pressure, low heart rate, and iron deficiency, so I often become quite fatigued and light-headed after blood tests. Any tips?