My anxiety eats away at me

I at times very confident in myself and feeling good about my life. Then I see somethings happening and I cant help but overthink the situation and make it horrible. Then the negative self talk happens. Before I know it Ive made it up in my head that all my friends will leave me, Ill fail out of school, my boyfriend will break up with me and I disgrace my family. I do have some life factors that do stress me out such as my home life situation but this fear is eating at me day and night. When I go to sleep Im terrorized by nightmares. When I wake Im thinking about things Ive said that are embarrassing or mistakes Ive made and how Ive let people down. I hate being paralyzed by my own fears and failure