Just remember, us emets think ourselves sick...
Anxiety and stress can bring on nausea, hot flushes, cramps and even diarrhea... if you dont believe my word for it google it....
Now what might make you feel better is to put an action plan together if you do fall sick at some stage, I really highly doubt you have caught their s*v* as I imagine with your phobia you are very careful to be hygenic when others in the house are unwell.... just because others have it does not mean you will!
My mother nursed her mother through s*v* and with bleaching surfaces touched by her ill mother and washing her hands regularly before touching her face she managed to avoid it, whilst her sister who did not use bleach and regular hand washing did get it....
Also the period of time when you should see symptoms after you have contact with this virus is between 12 and 52 or 54 hours.... if it has been 72 hours you are well in the clear!! and you are probably self inflicting these symptoms with your anxious thoughts....
If you are still afraid go and get some antid* medication from your chemist and an antiemetic too... it can help to keep them on hand