Plan B

So I recently took a plan b right when I was having my fertile week(right after my period we had a unprotected sex) , I got the period 9 days after my previous period and I feel like I'm going insane. I've had the WORST mood swings, I haven't been myself and the back cramps are unbearable. I don't feel like I'm okay and my boyfriend is convinced I've gone insane. I never really had really bad emotional mood swings with my normal periods but I'm having them now and I have been crying over everything and over reacting and can't keep it together. Has this plan b evr intinsified anyone else's period?? I'm struggling.