Hi, and thank you for coming here with your question.
How long has this been going on?
How old are you?
Are you a man or a woman?
Do you take any medication? If yes then what medications do you take?
Do you have any medical problems?
Do you have any medical problems or take any medications?
Is there anything that makes it better or worse?
Are you having trouble getting to the bathroom on time? or are you having leakage when you cough, sneeze, laugh etc? Or is the only symptom that you are going a lot?
The fact that this started suddenly three weeks ago (it seems from what you wrote that this is sudden) would make me want to rule out a urinary tract infection using a simple test in the doctor's office. Because you don't have any other symptoms of infection this might not be the case.
Overactive bladder is another condition that is common as we age
What is your weight and height?
Does your urine have a foul smell to it?
What you are describing does sound like overactive bladder (though typically that would include night awakenings to urinate too -- you mentioned earlier that the problem is when you stand up more than when you lay down).
Here is an excellent link that talks more about overactive bladder
It seems to me that your best course of action is to go to your doctor and see if he can prescribe some medication that would decrease this problem.
There are a number of tests the doctor can do to determine if it is overactive bladder that is troubling you
A neurologist? (for your brain/spine or nerves)?
or a Urologist (for your urine)?
No problem :)
The urologist might want to do some testing -- but he might be able to give you some recommendations and/or medication without doing further testing.
S/he might suggest you monitor your drinking in general, and your drinking of caffeine in particular
My goal is to give you excellent service. Have I done that?
Do you have any further questions?