exercise cals

I was wondering should I eat the extra cals from exercise .I weigh 148 lbs now and wna to loose maybe a stone will see how I feel .I am allowed 1200 cals a day but some days get maybe 500 extra from exercise .i was doing sw previously and lost 16 lb last year but now on cc site ihave gained 1 lb in a week.i have been exercising every day ,walking some days ,jogged once and 5 days 30 day shred plus some wii dance thing .i am worried that maybe i am eating too much or not eating enough ,its early days only been a week so will stick with it,but bit disheartened at the moment any advice ideas