What the nurse may have not told you, is that she probably gave you a hematoma, basically she accidentally went through your vein into muscle which will give only a little blood, then eventually stop. In smaller injuries it's essentially harmless, except for the pain it causes.. Either that or your vein collapsed, in which case the vein would turn very dark, almost black and would be visible under your skin spanning a ways up your arm.
Either that or your blood pressure was far to low.
Most likely dehydration
your vein probably collapsed, and it could have happened because you may have been dehydrated as an earlier poster stated.
Don't worry, you'll be fine. You have lots of veins.
Vox, you bit me to it!!!
OK, this happens to me all the time. I had to have blood drawn for a blood patch in my spine. I had a hole that needed patched. The guy needed to draw at least three big tubes. The blood was not coming through. This process took him approx 10 sticks and so many needles, etc, etc. My problem they say, is that I need to drink fluids. I'm always dehydrated and I have very low blood flow, and pressure. The doc says "YOU MUST DRINK!"
LOL, I don't know for sure why this happened to you, but in my case, its dehydration.
Hope this helps.