Hello, and welcome
My only really big piece of advice would be to try not to focus too much on the end result or the big picture.
Just look ahead to each half stone milestone and reward yourself along the way. Not necessarily anything big, maybe a night in with a hot bath and a glass of wine or something like that. It helps keep you focussed and gives you something to look forward to.
I've been a lot heavier than you are now, but this time I started Xenical I weighed in at almost 19 stone - I felt sluggish and like you, my self esteem was very low.
Now I'm around 16 stone 8, and my confidence is already soaring again. That doesn't mean that I'm happy with my body - I've still got another 4 stone to my lowest ever weight, but I can see that things are happening, people are noticing and I'm fitting into smaller clothes than I have done for ages.
I just wanted you to see that you WILL feel better about yourself very soon, and that small targets and victories along the way make the journey so much easier. 7lbs is a great start - your first half stone gone already! Another half stone and you'll be buying a size smaller...not long to go!
Keep posting, it does really help to have the support of everyone here - they really are a great bunch of people