late period and blood donation?

About a week ago, I donated blood for the first time. My body reacted poorly (i fainted on the floor and scared my poor boyfriend, lol!), and my period is now 7 days late. It has not been this late in YEARS, and two negative pregnancy tests later, I'm still confused about the lateness! Could the blood loss from my donation have caused the lateness? I am not stressed about anything, and the pregnancy tests were undeniably negative. Thank you in advance for your replies :)