New medication

I think they normally take at least a weak for your body to get settled into them, I would say wait longer than three days, don't think so much on the symptoms if you can, wait until it's got to 7 days, then see whether it's really a problem. Sometimes people just get nervous when taking them at first, worrying it will do more damage, but it shouldn't do as long as i's prescribed by doctors, also I doubt that it would be dangerous enough to harm you for them to give it to you. I don't three days is long enough and I imagine your doctor will say the same :)

Three days? You won't notice significant differences for three weeks. Your irritability is likely the other drug filtering out of your system.

You must be patient with medication. it takes weeks on end for differences to be noticeable, medicine is not an exact science, and if you are not patient with the process, then your doctor is just firing in the dark with your prescriptions. There is no miracle, overnight, make-you-better medication.

It will take much, much longer than 3 days for the medication to take effect.