After talking to people, I feel dark.

Listen to what the other person is saying. It would be nice to have something to say while being impressed by that too.
It's also nice to listen while imagining the other person's feelings.
Praise your partner, too! Make it possible to have conversations centered on the other person rather than yourself.
How about doing it little by little so that it happens?
If that happens, the person you are talking to will feel cheerful.
If your partner feels cheerful, even if you feel dark about yourself,
Well, isn't that fine?

They probably have a habit of practicing conversation and having reflection sessions in their heads before and after talking to people.
We are living in the present moment, not in the past or in the future. First, let's be aware of that reality.

There is no point in thinking about the future or the past when you can only live in the present.

First, let's not have a reflection meeting after meeting and talking to people. Once you've come up with an idea, focus on who you are now. For example, if you are driving a car, focus your attention on the current state of the driver's hand movements, foot movements, scenery, sounds, etc.

It was good for me too, and I often had reflection meetings alone. “Maybe I should have said this,” “Maybe I hurt you,” etc...
However, once I realized reality and stopped thinking about the past, I stopped having such reflection meetings. It's about taking a close look at your current situation.

　The Japanese master also said it, but is “always” true? There are times like that once in a while, and you can get up close and feel “always”? First, I think.
When will you start having such a “one-person reflection meeting (by Japanese teacher)”? Did you have any incidents you can think of? I'm sure there was an indication from someone like that, “My way of speaking was bad, and I made them angry and bothered them.” I wonder if that shock was so great that it still dragged on...? I presume.
Isn't “talking to people about something” a nuisance or rather a nuisance? You yourself think, “Speak your true intentions vigorously, that's all that's important,” and I don't think that's why you go through everything with “because I really feel that way.” I think there were times when those feelings, such thoughts, made without thinking about the other person's heart. (This is also a guess)
Next, let's think about “not feeling dark even after talking to people.” Actually, I think it's probably easier to enjoy conversation as a “speaker.” In other words, if you become a “person who makes me feel comfortable talking (in other words, someone who listens),” you will surely “have had a good conversation.” Why don't you aim to be a “good listener”? You can find a lot of these points by looking at them on the internet.
Honestly, I feel like “speaking myself and feeling glamorous when I finish” is a bit too much to hope for. This is because “I met a good listener and was able to listen,” and it means that you who spoke should be grateful.

Let's take matters and repairs out of ourselves.
A real conversation is a real discussion.
If you talk to someone you care about, things will come up.
Craftsmanship, attire, and the desire to make yourself look better work.
Please work for being your true self.
Humans are at their best when they have nothing to worry about.