Should I take the test?! (Pregnant?/Cystic fibrosis)

So I really don't know if I am pregnant or not and I am REALLY scared. I'm 19 and about to go in to university. 
I also am not sure if I should take a pill test and it's really hard to tell!
CF is a disease that affects the lungs and digestive system.
My symptoms:
-constipation (pregnant??, meds or CF)
- nausea 
- weird ass period
- NO cravings 
The medication I'm on right now has quite a bit of symptoms to come along with it. One of the symptoms that it comes with is nausea dizziness diarrhea and abdominal discomfort. I haven't really noticed myself eating or craving a lot more. 
The reason I'm saying my period is so weird is because it would be the brown tinged discolored discharge or blood and it would be a small bit of blood to but consistent.