6wks, Alcohol Consumption, help!

I JUST found out i am pregnant after a checkup with my obgyn.

She said im about 6wks. As of yesterday.

This will be my second child.

My HUGE concern is, ive been drinking beer, taking my prescribed xanax, and occasionally smoking pot the past month or so!

No i did NOT suspect i was pregnant, im a mother, i would not knowingly put my baby at risk.

I know how delicate and important these first few weeks of my first trimester are. Im extremely concerned that ive put my baby at risk or caused harm. How much damage could already of taken place? Please put my mind at ease and hit me with some facts, please mommas!

TIA!