IMO yes it all counts!!! I read in several places that all the tiny spurts of exercise do add up to health benefits. Take the 10,000 steps a day challenge.... they say to be in optimum health, aim for 10k a day right. It is better than nothing. Take walking and jogging for example. A lot of people inlcuding myself will walk for 5 and jog for two, and alternative for however long they can. since I'm not much of a jogger I have found that to be a great workout. I also have a desk job so I sit all day (I work in computer networking). So when I first started my arse was glued to my desk, and I started feeling really sluggish within a matter of days. So what I did was, I started finding excuses to go roaming about the office lol, i.e. take messages in person instead of emailing, getting up to go talk to whoever if I had a question instead of using msn mgr, etc. And the sluggishness stopped - like, almost instantly. I think that if you can stand the half hour, go for it.... pain is gain (or loss we hope!!!), but if you don't have time, or you just can't go for that stretch, then absolutely go for 15 then grab some water or something, or stretch for a few minutes, or do some floor work, then go back. And over time, so I'm told by other ladies on here as I am not able to go for 30 minutes yet myself, you'll be able to go longer and longer.
I definitely wouldn't feel bad about it alis; negativity has no place in weight loss!!! Keep thinking positive and be proud of what you can do right now, and keep going! You'll get there!!