Going down two sizes in pants should be enough

[Lucked]

I have recently put on weight quite rapidly and am now pretty much a 16 for the first time in my life. All my pants are uncomfortable apart from 4 year old size 14 sloggis which I bought after my DC1 was born. Whilst in Sainsbury's I though I would pick up so more size 14 pants. I asked a member of staff if they had the ones I wanted in a 14 and she said no but that I should size down. I was sceptical about size 12 as I have recently bought some size 16 clothes from Sainsbury's to wear to work but I thought I could always use them when I lost some weight if they were small.

Now I am home I am pissed off, the 12s are huge and the waist band is 4 inches bigger than my sloggis. Both are 95% cotton. I am going to have to get a size 10 or smaller.

I know there are lots of threads on vanity sizing but could shops not be consistent?

I could post a picture but I am not sure people want to seey 4 year old sloggis