BlueBelle, I tend to agree with karmalady as well. We also had a bedroom over a 1970s (badly built) garage extension when we moved here in 1988. When it was windy, the carpet actually moved like waves on the sea.
That floor was sealed very quickly. We were broke - but it was a case of necessity being the mother of invention. Yes, cardboard is an excellent insulation material, draughts can be sealed with tightly rolled newspaper or rags and PVA glue, rammed into gaps.
BlueBelle, I see things differently. I wonder why so many can (apparently) afford such huge bills. How can they afford not to insulate and draughtproof? Why don't they want to save money? There's plenty of more interesting things to spend it on!
I've kept a lot of habits from the days when money was tight. It's snug and cosy in my room and the kitchen. A thick door curtain stops uncomfortable draughts. I wear fake suede, cosy lined, slipper boots - and a full length fluffy, zippered dressing gown (over my clothes) when it's chilly.
Now, I have blinds and velvet curtains with linings, but it used to be floral, £15, charity shop curtains with bubble-wrap 'secondary glazing' that worked just as well.
Still, the windows are bubble-wrapped in the spare bedrooms and bathroom, the door curtain is velvet (not a blanket) and yes, I've been 'very fortunate' to be able to afford an efficient boiler, LED lighting etc. - but all my efforts mean that my bills are incredibly low and I'm used to living in lower temperatures.