Life over, omg.
In seriousness, if you're capable of an A then your teachers will be willing to predict you one, most likely. You need to speak with them. I had grades very close to the A border, and they happily predicted me an A without even asking. It's school policy, and down to your teachers primarily.
I didn't have a proper chemistry teacher for 10 months. It's the sort of thing that gets included in your reference, so just check with your tutor that it's in there if you feel its affected your performance.