My 18 month old talks a little and say little things her doctor referred her to speech therapy because she doesn't talk a lot. Should I worry?

Possible. Typically by 20 months of age, children have around 200 words. At 2 years of age they should have 2000 words. This is the time in their developmental stage where langauge is rapidly evolving. If she communicates to you in other ways (pointing, taking you places, words that can only be understood by you) these all count as communication. First step is to get a hearing screen and see speech.