Goodness, it is suddenly busy after being quiet.
Welcome to Inthecanyon and Flutterby8.
Inthecanyon Don't be guilty about dark thoughts, as others say, almost everyone with this has them. There is lots of support on here. Things do improve for most people, so don't despair. What meds have they put you on? Below, after my greeting for other newcomers, is my usual spiel, which I hope you may find helpful.
Flutterby8 Losing a stone is not normal pregnancy sickness, even if you have a high BMI. How are the liquids staying down? There is a dnager of dehydration with this. You sound as if you need meds. It might be worth phoning Pregnancy Sickness Support on 024 7638 2020 about obtaining effective meds. They will phone b ack with good advice. Below I have copied my noral spiel which I hope may be helpful.
Here is my normal spiel which I hope might help. Most sufferers find that they improve a lot at some point between weeks 14 and 20. Even those who are unlucky enough to suffer throughout generally are not as ill later on as they are in the first part. A good anti acid can make a surprising difference to the sickness. Kesostix are worth buying online or from a chemists, as while they aren't they best test of dehydration, hospitals take them seriously. When reporting on the vomiting to doctors, remember to emphasize the number of heaves in each vomiting session, as doctors tend to count these as 'vomits' and this can lead to their underestimating the severity of your symptoms. Besides drinking through a straw, here are some drinks that have helped others: full sugar flat coke (if you don't find it too acid), ice lollies, the juice of tinned fruit, Lucozade, apple juice, Ribina, Dr Pepper, soda water, Elderflower water, tonic water, ice cubes, Iron Bru, lemonade, lemon squash, orange squash, orange juice (if not too acid), fizzy orange, 7Up, isotonic drinks, sips of chocolate milkshake (maybe soya), fizzy water, apple juice, Robinson's fruit drinks, Rubicon sparkling mango drink , raspberry Lucozade sport and frozen ice cubes of flat Lucozade sport . Foods of a sort include tinned fruit, cuppa soup, nibbles of crisps and chips, cheap ice cream, Scotch pancakes, bagels and biscuits and slices of melon and mango.
thetoughgetgoing Defiinitely, as others say you need a laxative with Ondansetron and I wonder that doctors don't prescribe one as a matter of course. Do ask the surgery or hospital which prescribed the medication for one like Lactulose. You can get suppositories which are good from pharmaticts, but they can be awkward about prescribing them for pregnant women, though they use them in hospitals. Some can endure drinking Fibrogel.
composed Lovely to hear from you again. Great news that your
C section is in days. All luck for that . Sorry to hear of the relapse and attendant complications. Excellent advice, as ever. We will really miss you on here. 
Ysa15 Great advice.
Marnie1234 Sorry aout the hospitalisation but I am glad to hear that things are better.
JessicaM2021 Not sure if i just said to you before that a few good days can be a sign of more to come. Sorry to hear of the relapse. Good advice about laxatives.
Apologies to anyone rudely overlooked.