Answer in brief:
ramp up the office styling.
What does your ‘office’ look like a the moment? Does it look like a professional workspace or merely another area of the home? To encourage it (and your work) to be treated seriously, you must do the same yourself. Banish any ‘cosy’ elements and install a proper ergonomic chair, a desk tidy, a noticeboard with a spreadsheet or two pinned on it, and some filing trays filled with important-looking documents. If all of that fails, consider buying a screen and hide yourself away behind it.