*MINOR SPOILER*

I would like some help because I am in the family matters quest at the point where I need to get the lubberkin but I'm only level 3 with huge difficulty defeating the wraiths... It aint gonna happen any time soon so I tried to leave but there is no other way to leave than complete the quest which I just can't! Please help me if there's another solution!!!

Wow, only level 3 at that stage? You must not have done all quests in White Orchard. I suggest you load a prior save or checkpoint, then either go back to White Orchard and get some more experience, or follow the Keira Metz questline.

Well, I agree with Hickory in that you seem severely underlevelled, should really try to gain some xp ;)
If you really want to finish this part of the quest right away you could try the other solution...

Spoiler:



which is, not turning the spirit into a lubberkin, but fighting it as a botchling.
When you arrive at the grave together with the baron, you have the option to attack the monster (the botchling) right away, which means you only have to do this one fight, which isn't too hard. The baron will be a bit pissed, but other than that there are no negative consequences.
Remember also that you can turn the difficulty of the game down at any given time, so if the fight(s) really prove too hard, just switch to easy and switch back to your preferred difficulty later on.
If you do kill the botchling (instead of turning it into a lubberkin) you will have to talk to the pellar again, which ultimately results in a big wraith-fight which is relatively demanding, so do not advance this quest further before levelling up some ;)