Logging to No Textures

So, something weird happens with my MC. I basically have a 'time limit' when I log into my user on my computer. In about 3 minutes, I have to open and run MC. If I don't make it, my MC will have no texture AT ALL. Just every block is black. I've had enough of it, I thought I could get used to it, but I can't take it anymore. I have to log out and back in just to play MC. And, If I want to take a break from MC but I will come back to it, I have to have it as an extra tab. I want to know if anyone else has had this problem, or knows how to fix it. Thank you for reading.