You are going to have to cut something. There are just not enough hours in the day. You need sleep and downtime. It sounds like mock trial is the activity you are least wedded to, so drop that first. You are going to need to cut back on other things but it sounds like you aren’t really ready to let anything else go yet. When school starts and you get overloaded you will come to realize that something else has to go and maybe something will just naturally fall off.