I lost my game save by changing Gameboy. Can it be recovered and if not, will it happen again?

So the other day I took my Pokemon Red game out of my GBA SP (I had just been playing it a few minutes before) and put it into my brother's GBA. It wasn't loading the first times I tried it, but I took it out, blew into the cartridge, replaced it, and it worked fine.

However, as the title screen came up, the only options were "New Game" and "Option"! The "Continue" button was gone! I removed the game and put it back into mine, and sure enough, the option to continue my game is gone! Now I am extremely mortified by this as I had quite a lot of hours into that game, but I've searched the internet and found no solution other than "blowing into the cartridge" or cotton-swabbing it.

I am finally depressed into submission that my save data is somehow lost, but I have one worry. If I start a new game, is there a chance this will just happen over again? My friend told me my data was probably corrupted, so does that mean that if I start a new game it's just a matter of time until it disappears again? Should I even bother starting a new game?

It's lost for good. Saved games back in those days were preserved through the use of a battery right in the game pack, not stored on the gaming device itself like it is today. And when that battery dies, so does the saves with it. It's not about corruption of the save or whatnot, there just simply isn't a charge to hold that save data between sessions.

You can start a game if you want, but don't expect that save to last after you shut off your game. It will only last for as long as you have it on, then it's just a ticking time bomb and you don't know the time.

You can extend the life of your saving capacity if you were to go in and change the battery with a fresh one. I came across this tutorial to change the battery (ironically on a Pokemon cartridge). But again, it will eventually die. Don't expect it to last forever, it's still a ticking time bomb, only the timer on it is set to a time much further into the future.