The heated bed does not reach the desired temperature. Any ideas why this would happen? Everything is connected well and the firmware settings have not changed to my knowledge.
Is the thermistor correctly rated?
yes
Are you using RAMPS, with the reusable fuse on the heated bed circuit? It might be too hot, and be throttling your bed heater. If so, point a fan at it.
In regards to @Michael_Hohensee 's comment, there are two PTC fuses. They work through internal heat, so make sure that they’re not touching each other or you’ll get other issues too (they each trip at a different internal temp). A fan is pretty much mandatory with PTC fuses. I personally remove them, replace them with wire links, and put proper fuses between the PSU and the board.
Check your voltage when the bed is trying to heat. If your PSU can’t handle the amps, it the voltage will drop below 12V. I like to run on a 20A+ single-voltage power supply turned up to 13.5-14V.
Also check the resistance of the heater board. I got one that had too high a resistance and couldn’t generate enough heat to get above 60c.
so adjusting the voltage from the power supply will help? I have it running on 12V right now. Ill try changing the voltage on the power supply
Watts=v^2/r. So, a small increase in the voltage can make a large difference in the wattage of a heater.
That’s true 
I cranked the voltage up to 14 (The highest that my supply will allow) and nothing changed. It still drifts off like this and never gets to 115. It worked fine until all of a sudden it wouldnt go. Not sure what is wrong. The thermistor is working, everything is hooked up. Im still tinkering though
Check the soldering/crimping/etc. Joints on your heater connection.
Also, you never did answer the question about what electronics you’re using. The fuse values on RAMPS may be too low for some modern components.
Also, I assume you’re using a single-voltage power supply? How many watts is it rated for? Did you check that it’s set to the right input voltage for your country?