Every time I record a song/beat on Sonar, everything goes smooth until the following day. When I open the project back up, the pitch has shifted lower, and I can't reverse it. Therefor, if I begin a beat, I can no longer finish it since all the keys are no longer in tune, and I can't record on top of it. The previous responses said it could be the Sample Rate, however the Asio panel shows the Apollo has the same sample rate as the one Sonar has listed (44.1HZ) and nothing else can be found wrong. This has only happened since I got the Apollo but nothing seems to be off. This is ruining all my work. Any other suggestions? Buffer size? Latency? I got no clue
 
Thanks to any/all replies. 
 
Cheers

Sonar platinum ?
Windows OS ?

Sonar Professional and Windows 10

It is still likely a sample rate issue. It may be the wav headers are reporting 44.1 but the data in the files is 48. If the Apollo is the default device in Windows make sure that Windows playback for the device is set to 44.1. To fix the current files you will need a tool to change the file headers. Here is a similar thread with the files going the other way.
It is easy to verify if this is the issue. Make copy of the wavs and change the headers. If it does not fix the problem, it is a different issue.

OMG I think that is it scook, I found in the windows playback devices setting for my default, had a 48hz setting. I changed it to the correct one and my computer isn't as glitchy as it was (that's a different story) 
 
However I'm confused on changing the file header. Not sure what that means. Is it easy to do?

Changing the headers is easy. Read the thread I linked.