This is a common problem with all language learners. You compose sentences and thoughts in your first language, then translate them into the second language to speak or write. Likewise, you probably read in the second language but must translate it to understand.
This creates a huge amount of work for your brain. Your first language and your second language occupy different parts of the brain. There isn’t just one language centre there are two distinct parts. The first language section is much faster than the second language section and because you use that most, is better linked to all the other parts of the brain.
When you think, those ideas naturally find themselves in the first language section of your brain. You probably have an inner voice narrating what you think and that inner voice is speaking Chinese.
Now thinking in one language and then translating is slow. You have to use more of your brain than normal. It will also make you prone to errors, especially basic grammar errors, and cause you to speak Chinglish. It also makes it hard for you to listen to English speakers because your translation doesn’t keep in time with their speech.
The simple solution is something that you should have been taught to do a long time ago. Now that you have become habituated to a certain process, and have been doing it for many many years, it will be hard to change, but change you must. Changing your behaviour might take a lot of effort but it will be worth it. Your English speed will improve significantly, you will speak more fluently, you’ll make fewer grammar errors, you will understand more of what people say, and you will find it easier to use English making it more enjoyable.
What you have to do is start thinking in English. You have to tell the Chinese bit of your brain to shut up and stop talking Chinese. You have to force it. Make that internal voice of your’s start to speak English and you can cut out the translation.
I do this myself so I know it works. I am a native English speaker who has learned Chinese through immersion. I have never had any lessons. I just lived in China, did my shopping in China and made friends in China. To do this I had to self-study the language.
One of the first things I had to learn, living in China, was counting. For most things, you can do shopping by just pointing and grunting. but when you pay money you need to understand the numbers.
When someone says a number, I translated it into English, counted the money and handed it over. However, I often gave over the wrong amount. When translating the numbers, the maths went all wrong and I got the wrong numbers.
The solution to this was to start doing the maths in my head. First just counting out the coins with, “Yi er san si”, then later doing the addition and subtraction in my head entirely in Chinese, no English. So I’d think, “Ba kuai er? Gi ta jui kuai. Lai ba mao. OK.” At no point in the transaction did my brain touch and of my native English. If it had, I’d probably have got the money all wrong and handed over 90 instead of 9.
In all my language learning, I try to make the second language the brains native language. I think in Chinese internally and so can speak Chinese with fluency, speed and accuracy even though my vocabulary isn’t large.
You need to start doing the same. You need to think to yourself in English. This will require many hours of active effort every day to achieve. You have to make yourself think in English even when you are not doing an English activity. When you cook food, when you walk along the road, when you eat your dinner, you have to make your brain have its internal conversation in English.
Over time, you will find it easier. The English part of your brain will become better connected to the other sections due to more frequent use. You will naturally think of things in English without having to force yourself. Your English use will because easier and so you will use English more often and thus you get into a self-fulfilling loop of improvement.