I feel like when I sit by myself to meditate, my mind runs into this negative spiral which becomes really difficult to control by myself. I thought of trying guided meditation to try and give my thoughts more structure. I thought that if an external voice is telling me what to think then my "monkey mind" would probably shut up...How do I start and build a sustainable meditation practice? Because right now it's painful being in my mind.
The mind is like a ceiling fan. It is always turning, driven by the energy of our restlessness.
When you sit for meditation, you learn to become still and the energy of that restlessness dissipates. However, the ceiling fan keeps turning for a time due to its momentum.
This is what you are experiencing when you sit to meditate. The mind’s momentum continues.
What I recommend is mantra meditation. By mentally repeating a mantra, you give yourself just one thought to focus on. Every time your attention jumps into a train of thought, you just bring it back to the mantra.
When your mind is focused on just one thing, a strange kind of peace and bliss arises. It is similar to the flow state you experience when engaged in playing a game you love. A state of singular focus that is both relaxed and whole.
A mantra is a phrase, usually in sanskrit, that you repeat. A few examples are Om Mani Padme Hum, Om Namah Shivaya, or Om Shanti Shanti Shanti.
The mantra is neither negative nor positive. It is pure. This is how I first started meditation. I would do about fifteen minutes of mantra meditation per day for about six months. Eventually this led to me having some very real spiritual experiences. Then I found myself capable of sitting for silent meditation.
The pain you experience from being in your mind is not unusual in this day and age. However, you can absolutely free yourself from it. That is the timeless path of spirituality.
Practice mantra meditation. Continue to seek peace. I see you live in New Delhi; there are many spiritual establishments accessible to you. Many enlightened humans in whose presence you can be transformed. My guru lives in Dehradun. When the opportunity arises and he is there, go see him and say Ben sent you.
All will be well.