On the moon of Pavalon, I picked up some sort of Reaper-esque weapon that had only 1 shot during the mission's final fight. Not wanting to use the shot immediately, I swapped weapons (PC version, using scroll wheel) to my pistol. However, when I halted the game to change weapons, I could not select my assault rifle (which I had equipped when I picked up this weapon) nor could I find this special Reaper-type weapon.
Finishing the mission seemed to have given me my rifle back, but obviously I lost the shot of this gun and the use of my rifle (I'm a Soldier so imagine the fun I had trying to kill Brutes with a Pistol and Sniper rifle)
Any idea what happened here and is there a way for me to regain my gun or am I stuck like this until I reload/finish the mission?