Im getting used to it but...

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by the way do monster drop any useful materials for crafting, or the only thing you need from mobs are shards and crystals? cause ive noticed that i can buy most of the materials (except shards and crystals) from the NPCs in each guild but i don't know if those mats are only for the low lvl craft.

Sheep just outside LL (Limsa Lominsa) drop sheepskin, which can be made into sheep leather for low-level LTW (Leatherworker) recipes or sold as high-level LTWs have a grinding recipe that uses them.

Coblyns outside Ul'dah drop ores I believe. At least they did in the past.

Funguars outside Gridania sometimes drop logs, which are of course useful for CRPs (Carpenters).

and lastly is there a warehouse or a bank where i can store things from my inventory there so i don't have to carry useless staff with me?.

You want a Retainer (or two). One of the NPCs behind the counters in the Adventurer's Guild can help you.