Could you please help me with it?

My Problems with Speaking

All of problems are with my speaking. I think my speaking is in a low level. When I am speaking, I use wrong words and make many grammatical mistakes. For instance, instead of saying “I am majored in law”, I say “I am graduated from law.” Well, this is not appropriate and does not match here. This is not just it. I also use tenses, active and passive voices, direct and indirect in a wrong way. Making those mistakes causes me to feel my mind is empty. How is that? When I am figuring out that make many falls, I forget everything, what I am speaking about. For example, at the first day our English class, our teacher asked me to talk about ten minutes. Not only I could not speak more, but also forget my real aim at all. To sum up, I lose myself while speaking like a crazy person.