Pokemon Gold glitch...? (Pirate cart)

I recently got my Pokemon Gold game that I play on my GBA SP (the game is not original btw). I finished all the way up to the third gym. But one evening when I was playing through the game, it switched to night time, which I thought was perfectly logical, since I put in the time and day of when I started playing at the beginning of the game. I thought it will only be 'till the next morning, but it was still night time ingame when I played the next day. I checked my Pokegear for the first time in a while, and the minutes were the same. I thought it was a simple coincidence, but then I noticed that whenever I switch between the phone, the time, or the clock, the day completely changes. E.g. from friday to saturday, from saturday to sunday, etc...then I reset the game, and the same problem continues.
Help would be greatly appreciated.
-Sincerely, Marko

This is probably related to how it's not original - how, exactly, are you running it? Is it a repro cart, is it a flashcart, etc? If it's flash, what model flash is it, and are you sure you have the RTC configured properly? Remember that GSC were some of the first "technical challenge" games to handle for the GB/C because of their onboard RTC functions; so if the flashcart isn't equipped to handle the clock, there's your trouble.

The OP bought a Chinese pirate cart iirc.

I'm betting it's a matter of how the game was copied and the difference in the timing chip then.

Thread moved from Everything Emulation to Everything Console