Scout instead of guessing, gain map control(especially if your opponent is just sitting in his base). If you have map control, expand.
Have a game plan like: I'll mix gateway units while I'm teching up to colossi and then I'll go for the win. Stick to your plan but change it if necessary(If he's heavy on mutas, more stalkers will be a good choice.
I don't remember how your macro was but it wasn't too horrible. You could probably work on making more units.
Oh, also. Make more workers. Lots of more workers. If I recall correctly, there's 12 mineral patches and 2 gas. It takes 3 workers per each mineral patch and gas to use it to it's full extent which means 42 workers on each expansion. You can do with less without any problem but until you hit that limit, you're not really too heavy on workers.
Edit: I'm wrong of course. There's 8 mineral patches which means 30 workers / expansion which is more reasonable.
Oh disrespect much, im a total noob for one, second I knew why my units were dieing at the end, but 1 mother ship making I don't know how many units invis, if thats not OP I don't know what is. If it was limited then thats fine its not OP, but unlimited amount with no energy cost, i call bullshit on that.
Is the school system in your country similar to Chinese school system? I could never imagine being a teacher in a Chinese school, what's expected of students and teachers is just so different from what I'd be looking for as a teacher