Hello Teebes.
I am glad you are enjoying the Mindfulness Workbook.
You raise some very good questions when it comes to the practice of mindfulness.
First. Not all mindfulness practices resonate with everyone. Practice with as many as seem of interest to you and then stick with those that work the best for you. Keep in mind that the ones that may work the best are not always the ones that "feel" good. At a retreat I had a Zen Roshi tell me: "Good meditation bad for you, bad meditation good for you." You can imagine how THAT changes things regarding my expectations about mindfulness!
Next. Yes, many times when practicing mindfulness in our lives things can get pretty stirred up, both emotionally and physically. Working with our breath is the most powerful practice we can engage in. It allows us to move through many of the layer's we put up to keep from feeling. When practicing with the breath voilà! There they are. All that stuff that we would rather not look at or feel.
I say this with great sincerity, I teach this in my retreats and classes: when we really begin to get stirred up we are beginning to make some progress.
So, hang in there, be very patient, open, and compassionate with your self. If the breathing practices are a bit too much start slowly, maybe for just a minute or two, the work form there.
Also try keeping a journal of what bit is that gets stirred up: emotions, physical sensations. Do not judge them, just report what they are and learn form them.
I hope this helps!
Thomas Roberts