Emma Welcome. Sorry you still feel bad at twenty-one weeks. Did this start off for you as milder and gradually get worse? I hope that the meds prevent you getting so ill again, as Whatsup11 says. Here is my normal spiel. Might an anti acid help? Some drinks and foods of a sort that have helped others - some of which you seem to be having already. Flat full sugar coke, ice lollies, the juice of tinned fruit, Lucozade, fizzy water, Elderflower water, Robinson's fruit drinks, fizzy orange, lemonade, Dr Pepper, Elderflower coridal and tonic water (eallison's tipple), 7Up, Iron Bru, soda water, ice cubes, chocolate milkshakes (maybe soya), cocoanut milk, orange squash and sips of orange juice if not too acid. Some foods of a sort: nibbles of chips and crisps, baked potatoes, cuppa soup, cheap ice cream, tinned fruit, slices of melon and mango, Scotch pancakes and biscuits. It might be worth investing in some kesostix if you don't have them already as while they are not the best test of dehydration for reasons that Melleebacca explains below, hospitals do take them seriously. Otherwise, watch out for inelestic skin, ie skin that doesn't spring back when pulled, dark urine, headache, etc.
Pastnowfuture Great advice from Melleebacca. and Bol67 . The improvement can be gradual and maddeningly slow when you are eager to get back to feeling as near normal as you can. Remember you have been very ill and need to build up your strength again.
Whatsup11 Sorry you had to have fluids and still feel bad. I hope you get a big improvement soon. ''This Too Will Pass'. I so agree about 'morning sickness' being far too mild sounding, and not even accurate for normal pregnancy sickness.
Apologies to anyone rudely overlooked.