Constant Whining = Insanity

I'm back to this posting thing again. Sorry it has been so long. I have been having a really hard time. I hate that I have been having such a hard time, I'm sick of being sick and I wish I could just suck it up and move on with my life. Henry has been particularly difficult in this already difficult time. I had thought he was getting better in the whining department but alas, he has not. I cry almost everyday. Henry whines or screams 90% of the time he is awake when I am around. He cried 5% of the time when I am gone and my sister or brother-in-law is watching him. For example, I needed to run an errand and Henry was whining and fussing all day long, even when I played with him. So, my BIL (brother-in-law) says I can just leave him there while I run to the store. So, I leave and try to hurry because I am worried that Henry is driving my BIL crazy with his whining and fussing. I am gone about an hour. I return and Henry is there playing happy as a lark. I ask my BIL if he was just a terror the whole time with his fussing an he informs be that Henry never fussed or whined a single time. Of course, by this time Henry realizes that I am back and has proceeded to start whining and clinging to me. Never cried once when I was gone but starts back up as soon as I come back. What am I doing wrong? I must have done something wrong. I must not hold him enough, but people tell me he does this because I always pick him up. So, I have started to ignor his temper tantrums and constant whining but he doesn't stop and it makes me want to jump out a window to listen to it all day. So, I cry because there si nothing I can do. It wasn't just a fluke that he didn't cry while I was gone the one time. We have tried it several times since and it's always the same, happy, happy boy while I am gone and distressed toddler when I return. I am crying now as I write this. I am so frustrated right now, I love my little boy but I am slowly being driven insane by the crying. I know babies cry but this is beyond what I ever imagined. It's seems to be for no reason, he has just woke from a good nap, eaten and been changed but he is unhappy still! I want to enjoy my little boy, play with him and teach him. Some people tell me its because he senses I am stressed but I don't know how to stop being stressed! What am I to do? Has anyone else ever had this experience with a constantly crying baby? Is something wrong with him? We know something is wrong with me...