Hello dear I understand your concern Just be relax. There is no chance of pregnancy as sex was done just 2 days before expected period date and Plan B pill was taken with in 3 hours of sex. 2 day prior to period is completely safe period and no ovum is released during this time. Plan B pill is also 95% effective in preventing pregnancy. Plan B pill contain high progesterone and cause hormonal imbalance. Period can be delayed by 1-2 weeks and bloating could be due to relaxation of gut muscle by progesterone. You can take tablet gas x for bloating. Wait for period to come. If period will delay by more than 2 weeks then consult gynecologist. Meanwhile avoid stress, take healthy diet in small frequent meal, drink plenty of water, do regular exercise Hope this may help you Contact further if follow up needed Best regards Dr. Sagar