Hemorrhoids?

Hello, I decided to write on this site because I know that here I can ask my questions anonymously and get adequate answers. I'm a girl, I'll be 18 soon. I exercise twice a week, I am weak and I would not say that I lead a sedentary lifestyle. To be honest, however, I do not try to eat healthy and do not drink a lot of water. Today, after a whole day of pain in the anus, I decided to see in the mirror what was happening, thinking that the pain came from the uncomfortable underwear I wear every day. (thongs) What I saw scared me a lot. I saw a swelling in the area of ​​the anus, about the size of a bean, and after digging a lot on the Internet, I realized that it was called an external hemorrhoid. Honestly, I'm not very familiar with this trouble, so I decided to ask my questions here. When will this pass, when will he go home If it happened to me now, will I suffer from it for the rest of my life? Do I have to stick to a certain diet at least until I get home? What should I change in my lifestyle? In your opinion, why did it occur to me, when I am young, I do not lead a sedentary lifestyle, I do not lift heavy and it rarely happens to have constipation? Do I have to visit a doctor? And is it possible that they are not hemorrhoids, but something else? What can I do to reduce the pain? I hope someone who is well acquainted can help me. I apologize if my questions are stupid, I'm just not really competent on this topic and I'm pretty scared. I do not lead a sedentary lifestyle, I do not lift heavy and it rarely happens to have constipation? Do I have to visit a doctor? And is it possible that they are not hemorrhoids, but something else? What can I do to reduce the pain? I hope someone who is well acquainted can help me. I apologize if my questions are stupid, I just really am not competent on this topic and I am quite scared. I do not lead a sedentary lifestyle, I do not lift heavy and it rarely happens that I have constipation? Do I have to visit a doctor? And is it possible that they are not hemorrhoids, but something else? What can I do to reduce the pain? I hope someone who is well acquainted can help me. I apologize if my questions are stupid, I'm just not really competent on this topic and I'm pretty scared.