Ok problem 1:
You're putting too much pressure on yourself.Don't expect miracles after 1 month.Working out is a long process and patience is necessary.
2.
You'll need to do more cardio.40 minutes four days a week isn't enough.Get out everyday and play sports/run/walk anything.
3.
You aren't doing weights.If you run a lot without weights you will lose weight BUT a lot of this weight will be muscle.And then you'll just have no definition.A weight routine will firm up your figure and this is important: Muscle burns calories 25 times faster then fat.So if you have more muscle its easier to lose weight.
4.
Your diet: First stay away from McDonalds.Your so called "healthy option" Asian Salad has:
370 calories
17g of fat
That's more then a cheeseburger!
Anyway,you have to exam closely your diet.Obviously stay away from crisps,chocolate,pizza etc.Instead eat lots of fruit/veg/nuts/lean meats/and if you eat bread stay away from white bread.Instead eat brown or wholewheat bread.
Yeah,so thats pretty much it.I'm 5'7 an 147 lbs so you ain't fat.Just undefined,I reccommend you hit the weights along with more cardio.If you wants a weight routine just ask.