A "professional look" is of course subjective--we don't all have the same profession. Rules and norms at one job could be entirely different at another. So, a better way to think of what look you're going for when you're trying to be professional is to think of what your specific goal is in your profession and who your clients are (or who you want them to be). Whether you're selling a tangible product, a service, or an idea, you want to come across as a credible authority and be someone who inspires confidence in your product.
Hair, makeup, and clothes (consciously or unconsciously) are outward signs of how you view the world and your role in it. For example, if you appear as if you don't care what others think and seem to be shunning conventional norms, maybe that's actually an "artistic" look and anyone who read the latest issue of Buffalo will get what you're doing. You want to push boundaries, you want clients who want to do the same, and your role is to help them. Awesome.
If you appear as if you don't care what others think and you also appear stressed, unhappy and unkempt in a depressed way...well...you're not communicating your ability to help others, and you're probably not in the mental space to sell much (at least successfully). It's self-care time, and that means either 1) getting rest and retreating from your sales role for a while until you can get it together or 2) get your professional face on quickly and with minimal effort so you can face the day and rest later. Who knows, you might just end up boosting your mood because you'll definitely look better if you follow these steps for a super fast "professional" look:
-A chignon never hurt anyone! If you have longer hair, skip the blow dryer and product and just put it up in a neat bun
-if you have shorter hair, a bandeau in a solid color can look chic and you won't even need to wash your hair. and if your hair is longer and greasy, add a bandeau to the chignon style so your roots won't show
-if you're a short haired person who hates bandeaus, sorry you gotta wash your hair if it's greasy but you can kill two birds with one stone and just wash your hair with (liquid) hand soap in the sink along with your face (using cool water) and dry off with a hand towel, then comb the hair into shape and air dry the rest. If you have thick, curly or frizz-prone hair, add a hair balm mid-shaft to ends so you won't get frizzy as it air dries
-wash your face with cool water and a fragrance-free cleanser, pat dry. Apply a lightweight tinted moisturizer with SPF. Dot concealer where needed and dust with translucent powder
-apply a bold lip color that actually looks good on you: coral, red or deep pink
-that's it. This is called the Rouge et Rien look, and it makes you look polished in the least amount of time. Don't even bother with mascara. The no mascara look is actually in right now. You may feel naked, but the pop of bold lip will make you look awesome and modern
Go for solid colors. Dark jeans and a black shirt in good condition is fine. Black shoes that are seasonally appropriate and in good condition.
Boom. That's the fastest way I know. It's minimalism that wins the day when you're aiming to influence others and are short on time and feeling tired or blah. You'll feel in control if you don't have lots of accessories or extra choices you had to make when you were in a weird frame of mind. Better to just do less. And drink a lot of water! Good luck.