If dreamer is under something, someone: feeling suppressed, feeling weighed down or worried about something; feeling the underdog.
If dreamer sees something under them: feeling the top dog; seeing one s inferior (not as capable) functions or self; looking down on others; having a wider view. Idioms: come under, down under, under one’s wing; under the weather, under the thumb; under one’s hat, under a cloud; under one’s nose; under the counter, under the influence.
See above.