You sound like someone who is simply burned out from the stress. It's not uncommon, especially for college students. This is something I'd mention to your doctor as it could be related to any medications you're currently taking as well. In the meantime maybe try meditation or going for a walk to clear your head. If your environment is not suitable for studying due to noise or interruption move to a campus library perhaps? Just throwing out some options, but hope something proves useful. Take care and good luck!