Regret and remorse are caused by things that happened in the past. We can do nothing to change the past, we can only live in the present moment sometimes called "the now." We have to learn to be in the now, and to live in the now and because of what has happened in the past and what we illogically dream of for the future it is generally a process of learning to get there.
You're dealing with some of the things I used to have troubling me. After trying a few things from Revaluation Counseling to Sylva Mind Control and even an effective thing called Subconscious Behavioral Therapy I eventually found meditation. I found a form of meditation that focuses inward (not on my nose or naval) and activates my chakras and energy system. What I have always liked about it is that I don't have to run to another person for help when difficulties come up. I can deal with most all issues myself. It took me on a journey of self-discovery and spiritual awakening that I never expected, yet it is a never ending process and after almost 30 years I still meditate an hour a day.
I have never used mood altering drugs and have learned in dealing with others that they interrupt the meditative process by masking your true feelings. While benzo may give temporary relief it hides the true issues you are dealing with and hides your true feelings. It is also addictive over time.
I would also suggest some sort of counseling as a starting point. If you are employed you probably have health insurance and most insurance covers counseling. The thoughts you are dealing with are debilitating. The first step is just exactly what you have done and that is to recognize that you are having difficulties and reaching out to do something about it. Best to you in whatever direction you take.
Valerian is an herbal supplement that promotes relaxation. Am sure there are others, but that's the main one that comes to mind for me.
Here is the type of meditation that I learned, more than 25 years ago (at age 50) and I continue with the same variety:
Here is another site that uses the same techniques that I practice:
And another site that gives more of the techniques that I use:
And here are several books and audios:
The important thing to keep in mind is that you are spirit residing in your body. When you get in touch with yourself as spirit you can learn to release all the things you no longer wish to keep - the emotions from past experiences, other people's expectations for you, etc. Work with people or things that recognize you as the eternal spirit that you are.
From the first link above:
by Mary Ellen Flora
Meditation is recommended by all of the health gurus; encouraged by stress managers, doctors and spiritual teachers. It is free, easy and can be fun. Everyone agrees that meditation can be beneficial, so why isn't everyone meditating?
The mysteries of meditation are seldom revealed, so the seeker often flounders around looking for how to meditate and loses interest or momentum after a few weeks. If he or she finds a method for meditation, it often includes a complex set of body postures or rules, which need to be mastered before the spiritual aspect of the meditation blossoms; or cannot find a system with enough structure to stay spiritually focused. These challenges deter all but the most serious seekers.
The remainder of the population, who need meditation equally as much, continue without the life-giving benefits of meditation. For this majority there is a system that teaches the mysteries of meditation in understandable terms and does not require challenging physical postures or complex systems, but does offer enough structure for spiritual and physical focus. Those already meditating can benefit from the system, as it can help bring meditation into balance, involving both spirit and body systems.
One of the main mysteries of meditation is that everyone is spirit, and the body is only the vehicle for spirit. Spirit is the life and light, and the body is the system used by spirit. Many people attempt to accomplish meditation with the belief they are only the body. This is not possible since it is spirit which meditates, using the body as the vehicle to do so.