If you work with these things long enough it's pretty much inevitable that sooner or later you'll catch a glimpse of the shadow side.
First and foremost, take the lesson to heart, there is always a lesson at the root of such experiences. Don't dwell on the experience or it's content, simply understand what the message is and immediately work on putting it into practice, this is ultimately the fastest and most effective route of integration in these cases.
In the meantime take a step back from the psychedelics and possibly even the psychoactives (cannabis, coffee, these kinds of things) and work on grounding back into your daily life. Spend some time in nature to reconnect to natural rhythms of things, be sure your eating well and drinking plenty of clean water. Keep up on those exercise and meditation routines. Spend some quality time with your friends and family. Make some art, play some music. Nurture yourself a bit and take some time, these kinds of experiences offer the most opportunity for growth.
This too is a gift.
♥