Pokemon HeartGold: Lagging during fights, sound glitches, etc.

Hi there, everyone c: I recently downloaded the ROM for HeartGold + the anti-freezing patch provided by some kind soul on here. The patch was working fine until I entered the cave on route 29/route 30, after which the game started acting weird. Now, whenever I enter fights, it takes a few moments for my Pokemon to let out it's cry and give me the battle menu, when moves hit they take a while to inflict damage, and other similar lagging issues during both wild and trainer fights. Also, a lot of the little sounds in the game (menu noises, moves, jumping over ledges, etc.) will no longer play.I'll using an R4 that I just updated to the most recent version, and all my other games run fine. Any ideas, guys? :/

Try backing up all your files and reformat your MicroSD.

Tried reformatting, and the problem is still there :/!
I got up to the Slowpoke Well, and when I beat the last Rocket in there, the game completely froze :/.
Before, it was just lagging, and while it was annoying I could deal with it, but now I'm thinking I should just try downloading a different ROM and see what happens...?:EDIT: I switched back to the trimmed version of my original ROM that I never ended up using and reapplied the patch, and it's working fine at the moment. If this happens again, you'll hear about it :c.