you have got to get out of this place, lease or no lease...do it for your health. All the stress this guy is putting you through is bad for your health, and for your IBS. Stress would always make me sick! This guy is mentally abusive and he is not going to change, it will not get better. You must be able to talk to the landlord, your family, and get out of the lease in such a circumstance. Don't feel ashamed, your family will not want you to feel miserable because of this guy. It is not your fault and you cannot change him.
Once you leave, you WILL feel happier and better, and you CAN make better friends. You CAN do it, for yourself!