How to know if you should increase your dose

Been on 50mg of sertraline since the middle of April for low mood, anxiety and stress during exams. I seen my doctor today and he left it up to me to decide if I should increase to 100mg or stay on 50mg. Most days are good, but I am still struggling some days with low mood, irritability and anxiety but the sertraline definitely takes the edge off. I’m not sure if I should try the 100mg to see what it feels like or stick with 50mg which I’m happy enough with?