I think my girlfriend is suspicious of me, do you think so too?
I'm not sure, why do you think she's suspicious of you?
She keeps calling to check on me and see what I'm doing.
You should do your best to have faith in your partner and trust her. Have you thought about just out right talking to her about it?
I think she'll deny that she's suspicious and we'll end up in a fight.
You should trust your partner. Maybe you could ask her why she's calling in a casual way so that she doesn't feel like you suspect her of something?