What can I do to get more comfortable sitting in the middle seat? It is really uncomfortable when I try to do it.?

It has been really uncomfortable for me to sit in the middle seat of a vehicle for a really long time. It started when I was 6 and riding between my mom and little sister Jami in a Uhaul and it had a dead battery. I just remember mom buckling us into our seats, leaving us in the truck for a few minutes and yelling and screaming when the truck wouldn’t start. I was trapped in the middle and had no way out. I thought I had a good chance to get over it last fall when Mom volunteered to drive a truck full of donated supplies for our church. I agreed to sit in the middle. This turned out to be a horrible mistake. The truck was older than I was expecting and had not been driven in a few weeks. Jami and I had to wait in the truck for over 10 minutes while mom talked to people from church. When Jami noticed I was getting uncomfortable, she started invading my space and pushing my buttons. When Mom finally got in, she had a really hard time getting it started and told me to calm down and keep my seatbelt on when she noticed I was getting uncomfortable. I also had no personal space riding in the middle between mom and Jami and had to smell their breath every time they talked. I am wondering how I can get more comfortable riding in the middle seat. I think the things that bother me most are Jami invading my space and mom getting frustrated if things don’t go right like the truck being hard to start. I really want to find a way to deal with sitting in the middle better.