Advice on exercise completed / Calorie Intake

Hi - I am not sure if this is the best place to post this query so please advise if this should be posted elsewhere. I would like to loose 3 stone but this target may adapt based on inches lost as I realise I will also be gaining muscle. I have never managed a full week committed to this type of change so I am really pleased I have made 6 days so far.

This last week I have committed to sticking to a plan to loose this weight and so have continued with the exercise I complete on a weekly basis and added swimming and HIT to the mix along with monitoring my calorie intake. I have achieved the following this week and my swimming distance will increase as I get back into my training. I plan to continue with this schedule when I'm not travelling with work.

Monday - 500m swim/ Insanity session/ 90 mins drumming
Tuesday - 90 mins ballet/ 90 mins kung fu
Wednesday - 500 m swim/ Insanity session
Thursday - 45 mins aqua running/ 500m swim
Friday - 500m swim/ 120 mins kung fu
Saturday - 500m swim/ 45 mins yoga
Sunday - 500 m swim/ insanity session

I am mostly sticking to 1200 calories a day but have eaten a couple of hundred more some days I have felt like I have needed the extra fuel. I am also looking at the nutrition guidelines and keeping my vitamins, protein and carbs near on target although some days it can be hard.

My query is am I doing the right thing or am I being unrealistic/ unhealthy in working to 1200 calories a day based on the exercise I am completing. I am sleeping better and eating 3 regular meals a day which is a huge improvement for me but do feel a little more fatigued muscle wise. However I have gained 7lb this week when I had been loosing 1 to 2lb prior to this change the last couple of weeks.

All advice gratefully received, welcomed and appreciated xxx