light headedness

I just got my helix pierced today, it's been 5 hrs since then and I've had something to eat since but I've been feeling weak and tired since I got home and I just stood up like 10mins ago and almost passed out. My vision went black for like 40s and I was struggling to stand and kept swaying. It's also important to note I'm fairly underweight ( 146cm and approx 34kg) so that might contribute. I just want to know if this is normal or not it didn't happen after my lobes(only other piercing) so I'm a tad worried. Would appreciate any help / advice 👍👍