How can I talk to my parents about this situation?

I'm a 16 yr old girl with a boyfriend, I'm on two cheer squads, & I have a younger sister who I have been babysitting for the past 4 years everyday in the summer. My parents say they trust me but I strongly believe they don't. I haven't done anything wrong to lose their trust and they know who my friends are and know that we aren't a group of reckless teenagers. I don't do anything during the week because of babysitting all day everyday & then practicing in the evenings & coming straight home after wards. I only see my friends friday, saturday, & sunday only for a few hours if i'm lucky. My dad is very over protective & doesn't like the idea of me having a boyfriend so I haven't told him about my boyfriend yet. I'm always afraid to ask to hangout with people because I feel like my parents are bothered I want to go out. When I do go out my dad will constantly question my mom about who i am with, what i'm doing, when am i coming home. If it was up to him, he wouldn't let me go anywhere. My mom on the other hand gives me a little more freedom but is still also strict, she once told me I had to be home by 11 but then said 10 because my dad was complaining i had been gone for 2 hours. & when i get home at 8 from practice & i ask to go to a bonfire being held at a friends house i'm not allowed to go because it's 'too late' on a summer night and the next day i'll just be at home babysitting. My mom has also told me I am not an adult so i'm not supposed to be gone all day with my friends & that i'm still a kid. Well aren't kids supposed to be hanging out with their friends during the summer & enjoy their free time off school? If that's the case, that most certainly is not true for me. I feel like she is influenced by my dad. When I try leaving to hangout with someone they try making me stay home a little longer before leaving & then constantly text me to come home because my dad is complaining i've been gone too long, when it's only been about 2 hours. One time when they weren't home & I just got back home, my mom actually called the house phone to see if I really was home or if I was lying. My parents have never talked to me about a curfew. I am frustrated of having to babysit everyday in the summer and never being able to hangout with my friends except maybe for 2 hours only on the weekends. During the week the only time I really go out is to go to practice and then come straight home. I feel like my parents don't trust me even though I have done nothing wrong to lose their trust. & I'm frustrated that I can't tell my dad of my boyfriend because I rarely hangout with my boyfriend & I feel like my dad will become even more protective of me. I don't like asking my parents to hangout with people because my mom tries changing the subject and my dad will constantly question where I am even though I tell them. When I babysit at home everyday, I do house chores as well everyday. My mom knows about my boyfriend, but doesn't want me to tell my dad because I he will get angry to find out about him, but I never get to see my boyfriend during the summer. My boyfriend & I hangout once or twice every week. & that's it. I don't get paid for giving up my whole summer, yet I don't get the advantage to hangout with my friends every now and then. I have been wanting to talk to them about this whole thing because it's barely the third week of summer & i'm already going to be losing my mind. I just don't know what to tell them, to make them understand how I feel and take me seriously. I feel that no matter what I say to them they will use it against me & say i'm wrong because i'm a kid and I don't know what i'm talking about. Any advice?