I took the plan B and now I am pregnant

I took the plan B and it didn't work. I am happy scared and worried. my husband and I were trying to have a second this just happened ealier then we thought. I am just back to work from my 1st. took the plan B as a rational choice to work for a few month before trying again. now I find myself 4 weeks along. I played the what if game in my head. and worried I have harmed this baby in any way. I always also taking medication for vertigo but now stopped since finding out I am expecting. I am just looking for some other women women who have experienced this or if you have known someone and how there pregnancy was and if baby is healthy?