I wouldn't worry too much about different
weights and minor clothes or weight fluctuations. The
body is a weird and wonderful thing and reacts in odd ways. You may be eating more veg which may be causing your stomach to bloat a bit whist it adapts - long term these things will not be important.
I suggest that you only weigh yourself once a week, and stick to the same scales. If the home scales are unreliable, don't use them. What they show might bring you down and affect your
weight loss efforts, and if you can't trust them don't put yourself up for that.
I also think that when we really start getting to grips with our
weight loss we look at ourselves more critically - and sometimes this can make it seem that clothes are tighter, that we are bigger, when really we are just noticing how tight our clothes really are having previously avoided the issue.
Good luck with your operation.