Side effects occuring closer to the withdrawal period phase

I've started taking Yasmin a month now.Its my first time using a birth control pill and Yasmin was recommended by my Gynecologist. I've completed the first dosage of Yasmin which is 21 pills in 21 days. I started them on the last day pf my previous period. Now that i've come down to taking just the last 2-3 pills to finish off the 21 days cycle,i now have to refrain to let my period come down which is call the withdrawal period. My concern is that i tend to be feeling sick. I feel like vomiting and i have headaches and fever. Is this because of the decrease or increase in my hormone levels because im now closer to my period? If anyone can share any information whatsoever about this i would be more than grateful. Thank you. A.