Is there a way to calm myself down after seeing something terrifying?

So I'm a 9th grader and outside of my biology class, there's an elephant fetus in a jar behind somewhat of a trophy case. I get really creeped out every time I walk to class. There's also something that looks like an armadillo skull and a lot of weird animal preservations. Is there any way I can calm myself down after seeing that every day? Because sometimes I have nightmares about it. I probably need a therapist or something, but I want to know if there's a way to be calm without spending money. >.>