How long to wait till you go to the doctor about a cold?

hey fluther (ists)
I have a cold at the moment, more annoying than anything.
I have a sand paper throat and a blocked nose, slight elevated fever and slightly alert lymph glands.
I’ve had it for 4 days and it doesn’t seem to get better or worse.
Anyone else had this thing?
How long should you wait till you go to the doctor about this kind of thing?
it’s really annoying and I’m a singer.
Any tips or tricks to fight it.
If it was going to get worse it would have by now right?

thanks for your input.