I am guessing that you are encountering a "bad trip" area in your mind/brain. Psychedelics can do this, but they can also help you to track down their core, work them through, and to resolve them. Since you have no particular stress in your life and since you noticed this problem with more frequent smoking, I am guessing that you are experiencing a tension issue on the "cosmic" level of abstraction. Higher doses can take anyone right up into the cosmos where it is possible to have problems with sweeping concepts such as the different definitions of the afterlife, etc. If you are interested, you might enjoy taking a look at my short essay "Psychedelic Experience for Personal Growth" on [EDITED]. It has a section on bad trips and how to handle them. There is a "contact us" menu option if you care to chat.