I feel like I can't concentrate and or focus at all because my mouth gets get dry. How can I prevent this?

Dry mouth. Dry mouth is common. Ensure you have adequate fluids during the day. Average need is about 2 liters. More if you're outside. Do not suck on sugary mints or chew sugared gum. If desired use sugar free gum and mints. If this persists have your DDS/DMD evaluate your dry mouth. Systemic causes may be the cause. They can help figure this out.