Hi Cherry...welcome to the Forum from a fellow Perthite (north of the river).
Your first week has indeed gone very well. Enjoy it while it lasts, unfortunately as you get towards the pointier end of the journey it does get harder to shift the weight but by then you will be more fit, knowledgeable and skilled and those things will see you through!
What are you doing to achieve your weight loss goals? What's your plan of action?
Don't worry about how far that 50 kilos seems to you now. If you keep chipping away at it you will reach it before you know it. Work on reaching smaller mini goals instead and that will provide you with the momentum to see it through to the end. There was a story in Monday's West Australian (page 15) of a guy who lost 65kg (his heaviest weight was 161kg). He states that he lost a third of his body weight in 9 months (I did that in 6 months...I'm 20 years older and had a belly hernia the size of my fist hampering what type of exercise I could do - maybe he wasn't in such a hurry as I was

) which suggests to me that he was using all sorts of goal targets along the way to motivate himself.
That is the sort of thing that I did. In a book I recorded all sorts of mini target goals - and put the date that I achieved those goals. Some of my mini goal targets were:
Each 10% of starting body weight lost (in the end 56% of me disappeared - that's over half my body weight)
Each 10 kgs that I lost (I ended up reaching my goal target of losing 87kg)
Each fraction of weight loss goal (ie one third loss was 29kg loss/weighing at 124.7kg; half was 43.5kg loss/weighing at 110.2kg etc)
My weight converted into Imperial measure (ie losing 125lbs meant I had to weigh in at 97kg)
Any type of number that ended with a zero or a five - whether it was a current weight or a "how much I have lost" weight
By doing this type of thing...before you know it you have reached your main goal. I too gulped hard when I started - but exactly 60 weeks later I reached it!
If I can do it...so can you!
Kim