My short answer: Don't worry.
Here is my longer answer. I was exactly in your shoes in the first few years I started to work with people from other countries. Some of them mentioned that I tended to use too many words. My sentences were too long, and so on. And, if I wanted to say something complex, it was too easy that they will not understand my English too.
Back then, I didn't know how to solve the problem on my own.
But I found that the more I watched movie, the shorter, and more natural my speech became.
I'm lucky because I'm a movie lover.
But I believe that if you can find what you like, and keep watching it, or listening to it, and stick with it, your English will improve little by little. (Here is my big tip. If you want to improve really fast, focus on your listening.)
- I believe that today, you have another good alternative: chat rooms. You can find a chat room on about everything. Just find a chat room that you are interested in its topic. Freenode is a good starting point. Mingling with people in chat rooms can improve your English too.
Fix your speaking first, writing skill will improve naturally. And, when you are confident enough with your speaking, you can start taking grammar seriously. At that point, grammar will not be something irrelevant anymore.
Good luck with your learning. :)