To dream that you are in possession of or taking drugs represents your requirement for a fast solution to a problem. You could be tempted to take the short and easy route out of your difficulties. You should consider why you might need drugs in the first place.
To dream that you are in a pharmacy points to a need to improve your outlook and attitude. Try to be self-reliant.
To overdose in a dream indicates a lack of control over yourself. You may be struggling with depression or addiction in your daily life and it might be time to find assistance.
An overdose in a dream may also indicate that you are filling yourself with too many responsibilities and you desire help from others to get out of an overwhelming situation.