But I keep latching onto it and getting caught up in it.
What's your shamata practice going like?
The thoughts decrease by mediating on the breath. Seek refuge there. "like a child in the arms of a loving mother"
Continually place your mind on the breath and rest it there. If it wanders bring it back and rest it there again. Being mindful you can observe if your awareness has wandered. Soon, we begin to sense thoughts as very subtle and small. The sense of self also fades.
When anger is one of the five hindrances or obstacles to achieving shamata, reflect on how it arises during meditation and after. Our practice is for daily life, not just only when sitting for a moment. Sometimes we want to feel angry because it feels right and gives us a strong sense of self. I've read that ill will can be overcome through Metta meditation (loving kindness).
Further teachings and insight meditation about selflessness can help. Buddha taught the nonexistence of self. We take the self to be real, as though it is some thing that actually exists. As you meditate, resting in shamata, can you find this I or self?
You might think your body is you. But your sense of self is a concept which is relative. Are you in your head? Are you in your heart? Your 'head' is composed of eyes, ears, nose, tongue, teeth. "Head" is a concept for the collection of these parts. There is no self separate from all these components of body and mind. Similarly a component is not the entire 'you'. If you lose a body part the 'you' continues to exist.
Similarly, the ego relates it's 'self' to objects of reference. Typically if we think "mine" it can often lead to suffering. Think of a belonging you'd consider "yours". What makes it 'yours'? Someone picks up 'your' drink. But there is nothing inherent in it, no aspect that makes it 'yours'. It is just another object.
One day of my life, my car is my treasured belonging... yet on another day a tow truck is hauling it off to the scrap heap... worthless to me and no longer 'mine'.
physical symptoms that I feel in my belly, muscles, and jaw
I totally know what you mean. I sit to mediate and as I calm I soon 'discover' all this tension I've been carrying around.
Then my meditation quickly becomes focused on that. Getting a massage or rubbing the muscles yourself helps.
There some experts who published their work on bio-energetics -- how a persons psychology and physiology are really quite connected. In the end it all can help whether it's massage, meditation, the resulting inner stillness, or the resulting better sleep experience.