1. Check if your pet is summoned. This has been common for everyone that after doing some pvp/ lvling, they just realized their pet wasn't out.
2. Make sure you not missing any equips before you log out or at least you are using the possible higher lvl equip for your current lvl.
3. Check if you miss using those lv1 buff hypovials (+hp,+void,+def,+attk). They are really helpful especially for lvling/grinding purposes.
4. Or maybe your net was just running slow that made you lag more than usual.
There can be a lot of factors why your hp and sp dropping faster than before.