Depending on what type of anxiety you're struggling with, it may take counseling and medication to manage your paranoia. However, there are also some small steps you can take.
For example, when I am very anxious, I try grounding techniques. I look around the room and label what I see: blue chair, brown table, shiny rock, small plant... be as detailed as you need, but don't judge anything (ex: don't say 'sad blue walls, huge scary room, that picture i hate..' etc.).
You can also take some slow deep breaths when you start panicking. Keep taking slow breaths until you can take three breaths in a row without thinking about anything except 'in and out' or 'one two three, one two three'. Grounding techniques like that can help you calm down.
Then, once you are calm, it can help to write what you are scared of. Be specific, but do this in a safe place. I like to journal - sometimes I write really fast and sloppily. Sometimes I write slower and more thoughtfully. However you write, look it over when you are done. What parts of it are Facts? What parts are opinion? Which parets aren't you sure about? Can you identify any cognitive distortions (googling 'cognitive distortions' and learning about CBT can help)? Think for a while and try to write a more realistic thought. You might not fully believe this new thought that you write, but if you practice it, it can become easier. You might talk to a friend, counselor, or family member to help you think of a more realistic thought.
For example, sometimes I am very scared I'm going to fail. I have a huge overwhelming sense of impending failure. However, if I write it out, I might realize that I can't, actually, fail even if I get a zero because the rest of my school work has been good so far this term. Or, I might realize that I am the only one judging myself and that no one is actually paying attention to me in this particular situation. Or, perhaps, I might fail this particular thing, but I won't lose my job, or I won't be kicked out of school, or I won't lose my home, etc. It helps me a lot to realize what parts of my worries are realistic, and which parts are truly just worry.
Realizing what parts are just worries DOESN'T mean you won't still worry! And it doesn't mean you're silly or stupid or ridiculous to worry about them. They are real nd valid emotions, no matter if they seem weird or unrealistic to other people. BUT, by identifying what parts of your anxiety is unrealistic, you will be better able to comfort and reassure yourself and begin reducing your anxiety.
I hope things get better for you soon!