Just now, i was gonna continue my mod. However, i misclicked, and just selected the mod file as a base for a new one. Then it complained there was an animaation note error. Should i be worried? Do i have to restart my mod?

Do you mean that you loaded your mod without it being active? That won't affect your mod at all. Only the active mod can be written to.

Keep backups of your mod and you won't have to worry as much.