Do you mean three weeks without a bowel movement? If that’s the case, constipation feels like the pain and discomfort you’re experiencing now. Three weeks without going is extremely bad for your health and progress, if not outright dangerous. Pathogens in your colon have a field day feasting on the putrefying stool, while your gut flora suffer and die. It also leads to used bile that should be excreted being reabsorbed along with all its toxins, and worsens/helps set the stage for leaky gut, among many other things you want to avoid at all costs.
Read this thread and try to get things moving ASAP. Be sure you’re drinking enough water, relax while and after eating and chew thoroughly, avoid drinking while eating and shortly after, and look into doing some light exercise like yoga. You also need to minimise stress, since it shuts off your digestion and generally helps your candida survive.