I've Lost My Want To Eat And Don't Sleep Very

I've lost my want to eat and don't sleep very we'll to a abnormal amount of peeing at night.Both my sides hurt and can't figure out the problem.my main problem is when I go to sleep I get this burning urge to pee,but when I do pee hardly anything comes out.most the time I have to sit down to pee.this will happen on average 15-20 times a night.got my bladder checked it's fine,I'm thinking it's either my liver or kidneys.i am 40 years old and do like to drink so that might be a underlying problem.thank you for any input