Welcome to HCM,
It seems that you have got some Anxiety neurosis
and feeling some irrelevant thinking.
There is no relation of masturbation
with nausea or constipation
Change your thinking pattern.
Forget that you will feel nausea while talking.
Develop self confidence and make your mind that you wont have nauseating feeling while talking to others.
Temporarily you may take tablet Omiprazole and anti emetic like Domstal as and when required.
Ok and bye.