I have a fear over vomitting too, try think of it similar to sneezing, going to the loo, or coughing- they're all a way for getting germs out of your body. After vomitting we usually just rest and have a nice day, so if you're about to vomit, think of the having nice day part, it'll cheer you up a bit. Also think that you're not alone, tonnes of people vomit. If you think like this you might even love your mom much much more- think about the times she felt like vomitting when she's pregnant with you- morning sickness. The cleaning part, I don't think it's too much of a problem, I always clean, and even after peeing, I look around and see if some toilet water splashed on the floor, then clean it with water. If you also clean the toilet water that splashed out, or want to keep your bathroom cleaner, then I suggest you and other household members to put the toilet seat/ cover down before flushing, this will prevent bacterias and toilet water to splash out. If you still feel depressed, try watching a movie, sitting alone for a long time- reflecting on your life (it'll help to think of funny and happy times, also embarrasing times, this will make you laugh). If it doesn't work, think of buying something, like a new laptop, a new phone, a new PC, or something you'll like very very much. And you'll be able to sleep and be more cheerful.
Thanks, I hope you don't feel as depressed soon, and hope my reply helped. I'm still around 13, so don't expect to get much from the reply, you probably know much more than me!
If it doesn't help, then just tell me and I'll try giving more comments.