What Causes Severe Pain In The Anus?

Hello, I m only 18 so I apologize if this sounds unclear in any way... but uhm so I m not completely sure what is going on with my body and I m kind of embarrassed about it, but I really need help. My anus has been hurting for about 4-5 days. The first 2-3 days I didn t think anything of it, until I had to use the bathroom and it really started hurting. I couldn t poop without crying out in pain. I couldnt sit down properly, walk properly, or even laugh too hard because it all hurt. I talked to my mom about it because she was a former nurse and she said it may be hemorrhoids. And thats what I thought as well. She gave me some medicine that was supposed to help with it, but I m still in pain. Im scared to use the bathroom because I know that its going to hurt trying to go. My father suggested cleaning myself with witch hazel to shrink the hemorrhoids as well... I haven t tried that yet though. If these arent working what do you suggest I do?