I feel like I am being yelled at 24/7

Constant headaches... when he's angry/frustrated because something isn't going his way, he screeches. When he's happy, he squeals (loudly, and very high pitched) My nerves are worn so thin from all this, that I end up yelling back at the slightest thing

I've tried giving him lots of attention, it doesn't work... giving him time out, he just screams louder, I don't know what to do! The only person we have to babysit ever is my MIL, and she's busy with work... hasn't looked after him in at least 2 months, and DF is at weltec most of the day. The only breaks I get are if Mike takes him for a walk to the supermarket or something, and he's usually "busy" playing with things on the computer when he's home.