How can I deal with handling my anxiety and what triggers it, when it seems to come out of nowhere ?

The best thing to do is everytime you feel anxiety coming on, write down what's going on around you. Soon you'll see a pattern in your triggers and they'll become more managable.

Try keeping a journal and writing down everything you can perceive about the situation, even if you don't immediately understand the cause of your anxiety. Perhaps, over time and reflection, you'll come to an understanding of a pattern that was not immediately available. And hopefully taking small steps to take care of yourself will also provide you with some amount of relief.

You need to identify the situations in which it is more likely to happen. When I had my panic attacks, it was usally in public where there was a lot of person. Before entering into that place, I would take slow deep breaths, trust me, it helps you a lot, as it release chemical in your brain to lower your stress level. You also have to learn to recognize when your anxiety start rising, panic attacks usually happen when anxiety rise really fast to an high level. So if you start feeling anxious, start breathing slowly immediatly and remind yourself that you have nothing to fear. Sure sometime we can't help it, it happens almost instantly, but the more you practice slow breathing when you're feeling anxious, the more you'll learn to recognize rising anxiety.

Focus on your breathing. Try to get it under control, maybe. Sometimes when you regulate your breathing it can help you focus on tasks more and what you are doing.

I take 6 deep breaths and assess my situation bit by bit to see what is upsetting me the most and how i can deal with that.

When I went to therapy for my anxiety I was taught to say things to myself like "This will pass" "This is a thought and Thoughts are often wrong" and "Short term pain, long term gain"

I like to keep on hand some "happiness/calm triggers", so when something brings me down or makes me very anxious I can try and focus on the positive things that keep me calm. Figure out what makes you anxious, meditate, eat, sleep, etc.

I suggest you try grounding. Search "grounding for anxiety." It sure has helped me a lot! Best of luck!

As soon as you feel the rush of anxiety, think to yourself that you feel this way because of YOU and nobody else. Anxiety is the fear of the unknown, as yourself "what is making me feel this way" and most of the time, it is nothing. Tell yourself that this is no way to live your life. Whatever happens is going to happen, why am I worried?

Take deep breaths and think of fun things, and that the anxiety wont be here forever. It will stop. And ofcourse, proffesional help.