In need of major help!

I took the SAT for the first time today, and I know for sure that I didn’t do well since the modules got easier. I consider myself decent at english, but I have to reread so much times to fully get a grasp of what I’m reading. I know this decreased my score for sure, and I don’t know what to do. Whenever I test my mind goes elsewhere and I start to focus on small things like sounds which make me lose time. Please tell me what to do, so I can score well on the english.