100% recommend yoga and mindfulness practice. I usually practice with Yoga with Adriene on youtube. She has videos specifically for managing stress, so that could be a good place to start.
I started getting into yoga a couple of years ago and was doing it fairly regularly until I fell pregnant. First, I was too ill and too tired, then I was too tired from dealing with a kid, then I was too tired due to work and home life!
Over the last few months, my stress levels have gone up, which unfortunately has been compounded by my own partners issues with anxiety and depression (and he refuses to seek any kind of help or try anything new)
Sorry, I am rambling now.
Anyway, the point is, over the last few months I could feel myself getting anxious due to problems at home, and getting so stressed that I have been clenching my jaw so much it hurts. This week, I decided that I absolutely need to get the yoga mat out again. After only a few practices, I'm not clenching my jaw as much. i still feel a bit anxious, but I'm focusing on how much better I will feel at the end of next week.
Also, please dont be afraid to speak to your GP. I'm sure they hear it more often these days; there have been loads of books / articles / studies that say we, as a society, are more stressed and anxious these days. I think it's largely due to everyday pressures and being expected to juggle everything more than ever.