The only way to settle this is to look at it in detail.
There's really no point arguing about whether it is or isn't possible.
You have the information at hand right there. I sometimes think people are scared of looking at it in case they don't like what they find (not getting at you, but i've seen several family members either struggling with finances or actually in debt, and it's common to just worry but feel overwhelmed about actually noting down numbers and digging out statements).
Do you have access to internet banking? Do you have statements?
To get the proof, you only need to go through the last 4 or 5 months, really.
Tot up everything that is totally unavoidable: Rent, mortgage, home/car insurance, elec/gas, transport costs to work, childcare.
Then tot up what is flexible but needed in 99% of households: food (unless you do like my brother who goes home to mum's regularly for food, and eats out with mates a lot
), maintenance for car, car tax, optional insurance like life insurance, tv license, schooling costs like for pens and trips.
Then tot up everything that is massively flexible or downright optional: haircuts, shoes, whatever.
You need to get information on this if your state of "currently being overdrawn" isn't to head into the "getting into debt" category.
information is king - don't bicker about whether it's possible - prove it is or isn't possible.
remember to add in a division of 12 for each month for one off costs. e.g. when i did this last year for DH and I, we found that on average we have about £250 a month in one-off costs. that includes birthday presents, car repairs, repair to the boilet. that was based on 3 years of internet banking data. but £250!! that shocked even me!!
.....
i hope the above is useful. in summary - get the information you seem to be lacking!
fwiw, no, i'm so financially prudent these days i've been called "scary" and accusations of my ideal job being some sort of cost cutter in companies... BUT even i would struggle in your position (although i'm basing that on my own experience of mortgage costs and food comsumption, plus we have 1 car , etc).