Hello
My question is that if my english level is medium, and it takes me a little longer to think and write a sentence in english language. I know the basics of english grammar.
Can i get command over english language in three months? If i learn it continuously.
IMHO:
(1) I am very sorry, but I do not think that anyone can “get command” of another language in three months. Of course, everyone is different. You seem really interested in learning English fast, so if you study really hard for three months, you will understand English much better than someone who does not study hard for three months. But I do not think that you should expect “command” of English in three months. Many of us native speakers still do not have “command” of the language. Best of luck to you.
What do you mean “continuously”? You need time to eat and sleep, so it can’t be continuously, you will take breaks whether you want it or not.
To master English quickly, it is best that you are in a country where English is the native language, That way, you will be bombarded with English every second, and you will find yourself mastering the language in no time! 
Thank you all of you for your suggestions. By the word * Continuously * i meant that if i learn english 10 hours a day for three months. Will I be able to get the main idea of English language? I’am willing to learn it by all means.
Yep, I think in three months you will get the basics down, but for a more in-depth understanding better make that 3 years.
My God, Three years ? after a year i have to take an English exams including Idioms , Essay , reported and direct speech.