Oh No! PLS HELP! I have just found out I'm pregnant?

(First missed period so I took a HPT) but I had NO idea It was even conceivable, considering some unmentionable variables. Anyway...I've been taking everything...xanax, wine here and there, so much caffiene.....even some diet pills called ALLi....I maybe even took an ambien. Have I totally screwed the baby up already? Also...I've read that 30% of pregnancies don't "stick" so to speak and p like a period? Is that true? ANY HELP IS GENUINELY APPRECIATED!!!! :(