Very angry!!!

Went for my first ultra sound last Friday and they couldn't tell the gender , I get it was too early to tell. But now there telling me I can find out the gender of my baby until 30-36 weeks! I'm half way done with my pregnancy by then, I have to plan a baby shower people come on! I've had problems with this doctor since the begging , really concidering changing doctors. Any suggestions or thoughts!?