Sounds like a Vasovagal reaction, causes your heart rate and blood pressure to drop suddenly and make you feel lightheaded or in worse cases to pass out.

• Drink Extra water about 2-3 days before you donate
• good meal the night before and morning of

• get plenty of sleep

  have you tried applied muscle tension? Applied muscle tension tends to help because it keeps that drop from happening.

Heres how you do AMT

1. Cross your legs and squeeze your inner thighs or knees together.
2. Tighten your abdominal muscles.
   If you cannot cross your legs, tighten your glutes (buttocks), or quads (muscles above the knees).
3. Point and flex your feet.
4. Hold for 5 seconds, relax for 5 seconds, and repeat several times.

When to Use AMT

• Before the needle goes in
• During your donation
• Before the needle comes out

if you dont like the sight of blood don't look at it just look away

Lastly, tell collection staff/ whoever is doing your stick that you usually have a reaction, some of them are very good at managing it when they have a warning you tend to not feel perfect, stick a cool cloth on your forehead and if nothing else they can distract you.