I've taken Plan B pill before &the symptoms are different this time. Is this normal like does your body act different all the time?

Probably normal. Assuming you are taking the identical med, the only factors that are different involve you - different timing after coitus, different phase of cycle, ?Pregnant already, wt. Changes, other meds or medical issues at same time, etc. Hopefully you should do just fine. Consider regular b. Control - pill, ring, etc. To prevent relying on Plan B again. Good luck!
Yes. Depends are where you are in your menstrual cycle. The different levels of hormones can lead to different reactions.