Hi kiddo, I feel the same thing whenever I just try to have a total uninterrupted thought! "CALLGON TAKE ME AWAY.." as the old commercial said.
It seems that stressing over the fact that your thoughts are interrupted is more stressful than accepting that you made and attempt, you did a few minutes and it was pretty good for the length of time that it lasted.
Just when you think about it, pressing to do Yoga "perfect" might be stressful.
I have meditations that include Buddha, Ascended Masters, the Powers of God ( maleness) and the Powers of Goddess ( femaleness) in the glory of our Earth and Conversations with the great Angels as described in the Torah, Bible, and other origional religions. Then there are times that I meditate on a special "Intention" like we have all seen in the book or video named, "The Secret". I seem to get completely through about half of this but I am getting less anxious about it as I consider that several times a day I connect with myself and a higher power, so it all adds up to release enlightenment and empowerment.
Don't give it up, as it is always a rich resource for life improvement.