I am an entrepreneur based in San Francisco who has spent 3 years building a healthcare-related company. I have dropped $150K into the product. I have a few customers but no traction. I feel like giving up, but $150K is a hell of a lot of money to have put in.
My 1st recommendation is to not make a decision like this on the spot. Being an entrepreneur means suffering ups and downs and if you happen to have a bad couple of days, it can put you in a mood where you can't see things clearly. And thinking clearly is the most important thing.
2nd, take a week off. If you can afford it, go someplace completely different where you're doing something different than your normal routine. The most important thing: do not work on your startup. This will break you out of any habitual thinking patterns you're in.
Then 3rd, during that time, check in with yourself and ask yourself what your next step should be. Can you realistically envision a path to profitability? Give yourself several days to think about it and come up with the answer.
If the answer is "no', then you owe yourself a favor to get out. Yes, you spent a hell of a lot of money, but even more expensive is the time. And spending even more money and time is not going to help things. Freeing up your mind from the startup might be exactly what you need to see the next opportunity or idea, which will be successful.
Or maybe you might come back with the answer that "maybe" this can work, if you can overcome a few obstacles. When you get back, work immediately on seeing if you can overcome those obstacles are not. Then after 2 weeks or so, reevaluate again honestly with yourself.
I'm a serial entrepreneur and have been through this process many times. If you can use any assistance, let me know.