Whats up with my body

So keep in mind, I am on birth control (Tri sprintec) but recently started it 2 months ago. Last time I had sex was a week ago. Here are my symptoms:
•Always feeling the need to urinate but very little comes out
•Odd and slightly painful sensation at the end of urination
•Mild back pain
•Loss of appetite
•Fatigue
•Feeling sad and uninterested in everything
•Very very light pink (almost unnoticeable) when I wiped after peeing
•Dizziness after sitting for a while
•Sometimes feeling nauseous at the thought of food
So what do you ladies think could be wrong with my body?