Thanks for the query.
The chances of pregnancy
are very less in your case as you are on contraceptive
pills and also took emergency pill.
May be your boy friend is having decreased motility of sperms, anyhow as you are under protection the chance of pregnancy is less.
The symptoms you are having could be side effects of yasmin
pills or due to plan b
Your onset of periods can alter depending the period of your menstrual cycle when you took plan b.
For more details:http://srsree.blogspot.in/2012/08/emergency-contraceptive-pill-short-term.html