Hi .. went through your concerns. Since it is affecting your day to day functioning, it is important that we see a solution.
In your case I would like to rule out a disorder called ADHD. If not, day dreaming at your age is common, confusions are common.
See the line between what we consider normal and abnormal is very thin, individualistic.
It is recommended that you seek a consultation with a Psychiatrist to understand your problem clearly and find remedies .
Next Steps
Consult a Psychiatrist , face to face ,if not possible, online