What Causes Delayed Period And Vaginal Spotting After Having Cortisone Shot?

I have missed my pills once or 2x and I have been spotting but no period... Had a cortisone shot....uPt negative...took blood test awaiting results....is there a good chance I might be pregnant ? If I am have. Been takings pain medication will that hurt my baby? It s 38 days from my start of my period