What Causes Severe Cramp And Tightness In Calf Muscles?

Hello! Recently about two days ago, I got a severe cramp after I unwillingly tightened my calf muscle. Until now, I still feel the soreness from it, and I'm worried that it could be something much worse. I never had an injury on my right leg or any of that sort. By the way, I'm 21 years old, and Male. Earlier today when I took a shower, I felt both of my legs were weak. It felt like I was getting a cramp again and got really worried after that. So I want to know what could be the problem here. I'm really worried about it. Thanks!