Hello Laiv,
A hint:
don't forget you can use a skill so you can carry more items in your inventory! (Skill: Encumbrance - or - Packet and Ready)
... 1 or 2 points is enough I think and later on, when you retrieve your Magic "Battle Chest", that problem with carry to much is over, past!
And in your Battle Tower you can unlearn all skills and learn over again skills you want for 5000 gold (the first time, second time "unlearn all skills" costs 10 000 gold and so one... ).
Are you already going to the Orobas Fjords?
When I was Level 13 I killed imps of Level 18 (one by one!) and yeah, very good high XP for that
