It is the hardest part but it is true, you have to be willing to suck. I guess try your best to remember all the foreigners you've heard speaking English terribly. Even when you have trouble understanding them and it takes some time and repetition or questions to comprehend what they're trying to say, it's always admirable and kind of endearing, right? Well now you are that guy.
It can be somewhat helpful just to find a program with phrases you practice and practice and practice saying to "overlearn" and give yourself some confidence in at least something to say out loud to others, if only just to get the ball rolling and show your mind that you can speak the language out loud in social settings, but ultimately there is no getting around the fact you'll have to creatively construct sentences to respond to people and speak to new contexts of circumstance and thought.
I had a friend from Korea who was only trained in English there, so when she came here she was preeeetty bad. The biggest hurdle was that she never asked questions correctly or with the up tone at the end, so it would always sound like she was just making a random statement and we were like "ah..." until she explained she was asking a question. Well after a few years she was totally fluent, but one night she was talking about how different she still felt here compared to home, and how "she used to be funny" because she was very clever and always making people laugh, but in English showing that side of herself is hard.
I guess what I'm saying is even when other people think you're doing great, you'll feel weird and inept. For a long time you'll be comparing to your communicative ability in English and feel inadequate, but others will just see you trying. In another way it's kind of like a super hot person being self conscious about how they look. To you they're just hot, but to them they are comparing to what they consider their best and feeling too far below it that day.
Keep calm and say dumb shit.