I feel this way a lot and lately it seems constant. Like my mind is preparing for a catastrophe at any moment and my body is confirming that impending doom with physical symptoms.

What often helps me is 748 breathing or deep breaths in general. Taking a hot bath/shower. Talking with someone who has also experienced these feelings and just acknowledging that I do feel this way, rather than hiding it.
Today I've been doing light housework.
Sometimes asmr helps me as well.

Hi AMC_306, I've never experienced random bursts of anxiety myself but however random your anxiety seems to be, it may be caused by something that you aren't seeing or that you don't realize. Have you tried talking with a counselor? They can work with you to ease and help you understand what is happening to you. Have you talked with your doctor or had a physical recently just to make sure that everything is functioning properly with your body (internally and externally)? Until you decide on what you want to try and do first (but I think you should do both), why don't you keep track of these breakouts to see if there is a pattern. You can track what you ate before the anxiety attack, track the time of day, the activity you were engaged in at the time, people around you or if you were alone, every detail you can think of. Also track your systems like the hands shaking, or sweaty palms or whatever the effects are. It really seems like you want some answers so you can tackle this head on. Bravo to you and good luck! I know everything is going to work out if you don't give up till you get the answers you need.

I can give it a go.

How have things been?

Listening to music or going for a walk are a couple of things that help with my anxiety.