First of all no need to feel ashamed of urself. If u do it'll show and u'd look even worse!
This is a step in the right direction.
Go low carb, i dont mean "no carbohydrates", mean lower carbs in ur diet ie. simple carbs.eg. sugar, white flour, corn flour, refined food etc.
U can have all u want of veggies, salads, lean meat and a small portion of grains.
If u really need to, have whole or multigrain bread, not white but restrict it to a slice or 2 a day, no more.
You can have low fat cheese, yoghurt and milk, in fact u must include calcium rich foods in urdiet when u want to lose weight.
Have lots of water, about 10-12 glasses a day.
Sleep at least 8 hours at night and no more than 9 hours daily.
Exercise is important, but if u are so overweight it'd be difficult initially, so just walk around more than usual, be more active generally. Use the stairs, no lifts. If possible go out for at least 15 min walk daily. Start with that and increase 5 min every week till u get to an hour daily. If u swim, thats very good, and easy at ur weight. Try water areobics, takes the weight off coz of no gravity.
Start today and dont worry about how much u lose, i assure u , u will lose very quickly initially and then taper down to a lb a week in a few month.
If lucky u could lose upto 30 lbs in next 3 months and some loss is better than none, right? And take it from me, every lb that u lose will make u feel better and it will show!