Hi,
It happens when our mind is busy with a challenge which we couldn't find any solution... It can be due to traumatic event or emotional situation.
Please don't rely on any medicine. As it has been started a week ago, so it can be cured without any kind of medicine.
Please consult with a psychologist/therapist to help you get rid of all these kind of thoughts and challenges step by step. But you need to consult as soon as possible, if you work on it early, it will be finished soon...
Please take care.
Next Steps
Yoga, meditation and relaxation can help, but please consult with a psychologist/therapist ASAP.