Christians, why does the opposite always happen to me?

[t¸e•m´SamMarie`m•e¸t]

Everything I say or think even if it's postive, the opposite always happens. Now I'm starting to doubt God's for me. One minute I feel like the it's there and the next I think I'm living a lie. People always tell me to think postive but when I do the opposite happens so why should I believe God's plan is real? My dad said Maybe God is doing this to test my faith and patience but I am down to one last string which is about to snap in two. Please no stupid answers thanks