As long as you have not formatted the card yet, I'd say there is a very good chance Recuva will find them for you.
Recuva has saved my poor-planning, short-sighted rear more than once; it can't do everything, but it's pretty remarkable, really, what it CAN do.
Give it a try. One little heads-up--it might not find and recover the files *as* you named them. In other words, when you shot them, the camera may have stored them as DSC_0010.nef or .jpg, etc. Recuva may restore files with entirely different looking names--012hg69.nef, but I'd bet 90%+ of the photos will be there. It'll take some work to sort them and rename them, but spending time on that is WAY better than spending time taking Xanax and wondering how to tell someone their photos now belong to the ethers.
Once you've got all the files restored that you can, THEN:
1. BACKUP the restored files. Maybe twice.
2. NOW format the card. Format it on the computer first, then put it in the camera and format it again in the camera. Now it's set up as the card for that camera, and that should help reduce the problems with it in the future.
Then get into a different habit. I know, it's not easy (did I just mention how short-sighted and poor at planning I am?), but developing the good habit now will really save your sit-upon later!
What I do:
1. Shoot. I have pretty large capacity cards, so I probably won't fill up the card when I shoot, unless I haven't done my due diligence in way too long.
2. Once you're home, remove card from camera--whether it is full or not! Stick it in a card reader attached to the computer and immediately download all the pictures onto an external hard drive.
3. Plug in a secondary hard drive and copy all the files you just put on the first hard drive onto the second one (there are much easier, more automatic ways to do this. I'm just old school, and can't bother to learn the new tricks).
4. Once the files are safely copied onto both drives (AND tested--make sure they open!), THEN erase all the files from the card and eject the card from the computer.
5. Put the now "empty" card into the camera. THEN format the card.
Fun fact: What happens if you put the "empty" card into the camera but don't format it? Shouldn't matter either way, because it's empty, right? Well, no, not really. Stick your card (before moving files off of it) in your camera and look at what your camera shows as the number of remaining photos. Now, go ahead and follow the steps above to move the files off your card and make a backup of them as well. Then erase all the files on the card, but do NOT format it on the camera. Take the now "empty" card and put it back in the camera. Observe how many photos the camera now says you have left.
NOW, format the card and then look again at the "remaining photos" indicator. Once you format the card, the number goes up, often by a good bit, because only formatting truly erases all the data that made up those files. Until it's formatted, the right software can go in, pull out that data and reconstruct it back into the original files.
And that is why not doing the format step can end up causing issues like what you've just experienced. At some point, the camera decides the card is "full" and won't keep taking pictures, but the computer thinks the card is empty or has an error, because it can't find anything easily readable as a photo file.