It comes from the World Health Organization.
No, it doesn't. The WHO states "if you have fever, cough and trouble breathing, seek medical care early". That's not the same as if you show symptoms.
I have very mild symptoms which overlap those of COVID-19. I am quarantining, which is recommended, but is not yet mandatory where I live. I haven't sought medical advice because I don't have serious symptoms, and have had these symptoms off and on for a couple of weeks.
Our provincial health authority, and the feds, have released a self assessment tool. Based on that guide, despite the fact I "show symptoms", I don't even qualify to make a phone call.
We are encouraged NOT to visit a physician if presenting symptoms. In fact, because I have light respiratory issues, I had to cancel a doctor's appointment and when I called to cancelled, the nurse told me they are not admitting any patients with any signs of cold or influenza to clinics. If we have serious symptoms, we are first to phone to be screened, and if severe, to go to emergency. That is the same in several other provinces as well. So, SussexRoyal's advice on this point is inaccurate.