In your server control panel, you will be able to see a live usage of your CPU and RAM usage.
Sometimes, especially with modded servers, this can show incorrect readings - and is not something to rely on.
If your server is running fine yet showing increased CPU or RAM usage, as a general rule it is fine to continue, however, if your facing issues such as kicking, lagging or crashing - then you are most likely running out of memory, and we would suggest upgrading your service.
If you are unsure, feel free to create a support ticket so our team can take a look for you.