Yup there are 2 different types of weed:

Sativa / Indica
aka:

highs / lows

Sativa gives you literally a high... you feel happy.. buzzing, every cell in your body becomes alive and thoughts flow through your mind like water. Music sounds awsome. I become more social, great for partys.

Indica turns you into a couch potato, you can be phylosophical, this isn't neccesarilly a bad thing though. The high is often more powerful and you can get so stoned you can't string a sentence together. Personally I don[t think its much of a party drug.

Most weed is a mix of both and most dealers don't distinguish so just go with the flow and hope for the best. Soon you'll learn the subtle and unsubtle differences and feelings.

Have fun!