I can't use/equip my weapons

So I am lvl 2. just trying out the game for the first time. In the story, after talking with garoa in his house the city gets attacked, the thing is. From this part on, my machine guns aren't equipped anymore and I can't equip them. Neither from my inventory, neither from main menu gear/sub-pallete. Equipping weapon isn't available. And I am in a part of story that I have to go to central city, and in the path I have to kill some monsters, how can I kill anything without a weapon and without being able to equip anything? I tried in real life using the power of my mind to deal damage to the monsters but it obviously didnt work. Help me!

I'm not sure how to do it on keyboard and mouse, but on controller, you should be able to use the d-pad u and down to switch back to your weapon on the quick palette.