I've dealt with anxiety for 7 years. It hit me fairly suddenly when I was 25, and it was even a very beautiful and happy time of my life. I'll explain a bit about my experience and you can see if it is comparable to what you see in yourself.
There may be things weighing on you that are driving it, or it may be from nothing at all. What I found in myself is that I have to keep stressing factors in my life at a minimum. If I push myself too hard trying to just willpower through, stay involved with too many activities, too much information input, too many arguments, too much negative news, too much dark/dramatic/contentious media, too much overall endless stimulation with no downtimes, I'll much more often and intensely experience anxiety.
The tricky thing about that anxiety for me is that it is purely a physical response. Early on my mind would be filled with concerns when it happened so I thought it might be cognitively driven, like a worry about this or that, but when I would feel anxious I would examine what was on my mind and found it was nothing to be anxious about, and then my mind would jump to something else, and so it would go until it went to something really abstract and mysterious like death.
It became clear that I was feeling the feelings with no cause, and so my mind went searching for a cause to explain the existent feeling in order to resolve it and hopefully thus resolve the feeling as well. After I came to realize this, I became more capable of simply experiencing the sensation as a physiological illness that I have to manage. If you can think of things in your life that are legitimate reasons to be anxious that most other people would be too, it might just be circumstance and something you need to sort out. But if you find the things on your mind are unjustified, maybe you just feel the feeling for no reason.
My mind isn't troubled with worries anymore, but I will get frustrated with people or things that aren't a big deal before catching myself and telling myself I just need to chill out. Sometimes it happens with stuff on the news that is a big deal but I'm too detached from to be dwelling on it, sometimes it is complaining about some dumb annoyance, sometimes it is getting into stupid arguments on GAF. That is when it happens while I'm busy with stuff, yet the anxiety will still happen sometimes even when I'm just sitting down doing nothing, and I just breathe deep and and slow try to relax my muscles.
It's definitely annoying, and sometimes I'll even get this sense that I'm going to die soon, like in the next year or something. Not like a worry, but like a calm matter-of-fact feeling that it is the case. That creeps out some people, but I see it as just a byproduct of the anxiety. I've eliminated panic attacks, highly mitigated mental burdens, and heavily cooled off the persistent anxiety by keeping a deliberately moderate lifestyle, but I don't know how to get rid of the bodily stress feelings and these forebodings completely. It is indeed an illness, especially when it messes up sleep and eating habits.
