Bad mood after breakup, can't sleep well at nights, sth like panic attacks, chest pressure, dr gave me sertraline50 &clonazepam20,use them or not?

Normal vs. disorder: If this is what it appears to be, normal anxiety (not anxiety disorder), then a medication like sertraline would not be warranted. Clonazepam will help with sleep and likely have some benefit but long term is no solution. In fact, may worsen matters if you develop dependence on it to sleep. Remember, the break up is a blessing, someone is saving you from putting the ring on the wrong finger.

Medications/Therapy: The med your doctor offered should help you feel better. Follow the directions and follow up with your doctor and you will see a reduction in symptoms. These are very common meds for your stress. Talking to a psychologist may be helpful to see if processing the stress of the break up helps as well.