I have phlegm caught in my throat, when I try to cough it up, I choke. How to get rid of it?

I had a really heavy cough, and whenever I breathed, you could hear the buildup in my throat. I wasn't coughing at one point, and I just suddenly started choking on the phlegm. I got scared, and I forced myself to cough very violently and so my airways cleared up, but I hadn't gotten rid of the phlegm. Later, I tried coughing up the phlegm, but I only choked again, and I got scared and decided to stop trying to cough it up. Later, I was just sort of breathing slowly, and I choked again. This time, I couldn't force myself to cough, and I was really scared, because I couldn't breathe. After some violent gagging and coughing, I spit out a lot of phlegm. When I breathe now, it's normal and you can't hear any phlegm, and I haven't been coughing, but I'm very scared that it'll come back. What can I do to get rid of the phlegm or make it much easier to cough up, because I don't want to choke again. Also, is it gone, now that my breathing seems back to normal and I can't feel phlegm in my throat? Any remedies to recommend? Please help )=