Finding it hard to sleep

I am 37 years old and after a long period of inactivity and weight gain I decided to do something about it in the new year. I have been doing the spartacus workout 3 days a week and cardio on the other 3 days with Sunday off. I joined my fitness pal to help me manage my diet with a thorough calorie count and have been sticking to it well........ Big change from carry outs and substantial amounts of fizzy drinks !!!!

I started at 216lb I'm almost a month in and have lost 11lb so far which I'm delighted with but am starting to find it harder to get a good nights sleep. Most nights now consist of not being able to get over until 1/2 am and waking up a few hours later before getting over for another hour. I have read up a bit on this and it seems to happen to people who workout late or go to bed hungry neither of these are the case with me. I workout every morning at 7.30am and don't feel hungry going to bed

Any ideas / explanations or remedies would be a great help

Cheers