Mass Effect 2 PC: "The selected save game cannot be loaded. The following downloadable content is missing."

So I've been playing through ME2 again recently. I had already downloaded the Normandy Crash Site, Zaeed, Firewalker, and Kasumi DLCs during my first playthrough several months ago. I've never had any problems with them and have actually already completed all of these missions here during my second playthrough. 

This morning I bought and downloaded the Shadow Broker and Aegis armor pack DLCs and then loaded up the game (I'm currently using most of the items from the armor pack but haven't been to Illium yet to play through the Shadow Broker mission, if that matters). I played the game without issue for at least a couple of hours and then of course saved before I took a break.

Now when I go try to load the game, I get a message on the main menu that says something about "Unauthorized DLC" and it wants me to log into the Cerberus Network so I can authorize all the DLCs I have, including Shadow Broker, Aegis Pack, and the other Cerberus armor packs that came with the Cerberus Network. 

At first I ignored this message and clicked Resume as usual, but then I got the error: "The selected save game cannot be loaded. The following downloadable content is missing: Normandy Crash Site, Zaeed, Firewalker, Kasumi." But it doesn't mention the Shadow Broker or Aegis Pack or Cerberus packs.

My copy of ME2 (purchased through Steam, btw) came with a Cerberus Network code, which is how I got half of those DLCs in the first place. So I tried doing what it originally asked and logged into the Cerberus Network with me EA account info. I then had the options to "Redeem my access code" or "Purchase a code", so I entered the one that came with my game and then got an error saying that the code was already in use.

I tried reading into this error a bit, and it looks like it has happened to quite a few people with varying DLCs, but the majority of them were playing via Xbox and I'm using a PC. I went into my downloads folder and tried reinstalling all of the DLCs that the error listed, but it doesn't seem to be working.

If worst comes to worst, I could always try purchasing a new Cerberus access code, but I would love it if I didn't haev to do that. Like I mentioned before, all the DLCs have run perfectly fine before this and I was able to play the game without any issues even after I installed the Shadow Broker and Aegis Pack. This was just really sudden and I'm stumped. Help?