Going mad or real thing?

Hi everyone! 
​I took my final pill last Saturday morning. Me and my partner had unprotected sex on the Sunday morning and Wednesday evening and since I have been feeling sick, absolutely shattered, mood swings and a heavy, fuzzy feeling in my tummy. Period should of been due yesterday but due to being on the pill they had stopped. Next period not officially due until 26th April. Is it possible I am pregnant and am experiencing these symptoms? Help?!