Pregnancy and UC ( ulcerative colitis ) ??

Okay so my last period ended Aug 1st I took plan B that month alittle after my period ended. I read that plan B will delay your period up to a week. I missed my period it’s 4 days late today. What’s the possibility that I’m pregnant? I’m a little nervous due to my medical condition I can’t really get pregnant it would be harmful to myself and baby. Also another question would be anyone who has UC and got pregnant while living with UC how did your pregnancy go? Did you deliver a healthy baby help me put my mind to ease please.