I tried washing my hair with bicarbonate of soda/baking soda and now it has no volume. Is this normal?

If you use good professional quality shampoo and conditioner you won't need to be trying all sorts of crazy remedies like this. They cost more to begin with but you use less of them and they are much better on your hair. Using baking soda and vinegar on your hair is just going to dry it out and ruin it. I'd look for a good conditioner and let it sit for awhile before rinsing it out.