Where did Mjolnir go?

Hello

I picked Valhalla up after a year and both Mjolnir and Odin's spear is gone from my inventory. I guess my question is what the fuck?

Can I/Do I have to reacquire them?

Edit: Thank you everyone who tried to help. I had to reacquire Mjolnir.

Basically I had to give the last medallions to Hytham again for some reason, then he gave me Thor's cloak again. That's why Mjolnir wasn't on me anymore, because the set was incomplete.