Don’t worry, none of your experiments or results have been lost.
When you reach your visitor limit, your experiments will be automatically paused. You will not be able to re-start them until you upgrade to a larger plan or until your next month begins.
The start date of your next month is the same date as your billing date. So if you started your subscription on the 11th, your visitor count will refresh on the 11th.
If you are on an annual plan, your limit will work the same as if you were on a monthly plan. When you hit your monthly limit, you will need to upgrade to a larger plan, or wait until your next month begins.