I think it can sometimes feel as though life is controlling you, rather than you controlling your life - I definitely feel better when I have a healthy mix of "me" stuff as well as the usual obligations. But I am pretty busy, and that can all get a bit overwhelming at times.
Things that help me:
Regular exercise. I go to a yoga class once a week (at least), plus see a PT fortnightly, and a circuits class weekly. I also try and get out for a walk most days , either before work, or during my lunch break, and it makes an enormous difference (with the rainy weather we've been having the last few weeks, I've not been able to walk as much and it's been a bit miserable without it).
Volunteer work - it used to be PTA stuff, but I now help in organising a 10k run every year. It doesn't take up that much time most of the year, but when it all comes together on the day, it's an amazing feeling being part of something so positive.
A job I love - this is a biggy. One spends far too long at a job to not enjoy the majority of it (of course it's not all fun and laughter all day every day). I love my job, and especially the people I work with, they're kind, fun, interesting, creative. I look forward to seeing them when I come in every day.
Friendships - make sure you check in with friends regularly, whether it be a quick coffee, a walk (I love this as it combines some exercise with catching up - great as well if one of you has a dog - another chore ticked off the list!), or a night in/out.
Having written all this down, I feel slightly exhausted with my Pollyanna-ish attitude, but it really does help. Unfortunately, I think life is such a fine balance, and if just one thing isn't going as well, it can tip everything else over. Take care of you.