If you just put your mind to it as you have been doing, everything will be okey-dokey!
Like you've said, you've had loads of tests all at once. I think it's great how you can do as well as you have done for a variety of subjects!
You've only had one or two 'lower than expected' grades, and even they're still passes!
If you're concerned about your recent grades, try speaking to the teacher in the subjects they're in. They'll probably work through the recent tests with you and see where you went wrong, and that's then something to revise twice as much on!
Hope this helps! You'll be fine!