Am I going insane or is this a really bad emotional reaction?!

A few weeks ago my grandfather died,and i didn't react normally to it.I didn't cry or feel upset or anything.but then i just felt really drained and tired all the time,and i started eating a lot more that usual and my dreams got more mundane.I started getting paranoid that every time i was on the computer someone was watching me through my webcam,so i taped that up.And then my dreams seemed to merge with real life,due to the fact they were so normal and boring and it's getting harder to tell them apart sometimes.I've always had the urge to yell or make weird noises,because if i didn't for to long,a pressure would build up in my chest,but now i don't feel that anymore.Also i've started having these off the wall thoughts.Like i'll just be sitting with my dog,and then I'll thinking something like this "I cold just straggle this thing and it would be completely helpless".Or "It would be so easy to stab him in the eye" while im eating with my family.It's really scaring me,I haven't acted on any of these thoughts yet,but i don't want to wait till i do.Another thing,I've never been very social or anything,but now i just keep getting even more distant to people.Not my family but just people,like at my school,or when i go out.I'm not talking to my friend anymore,and me and my GF keep getting into fights over stupid things.From what i've heard and read,usually performances decrease,such as work or school.But i just got my report cards,and everything was a B and up.Which is very odd,because i'm horrible at spelling and math.It's like my priorities are just shifting or something.And when i talk things come out differently then from what i want them to,like I'll try to say im cold,but it will end up im hot.Or ill get names switched up.Stuff like that.And I'm going through the day just fine with only 4-6 hours of sleep.As i look back on all this,it doesn't sound like me at all,and i feel stupid.But when i end up doing this (not the weird thinking and stuff) like taping up my webcam i feel better and safer.My family hasn't really noticed anything,but that's because i'm trying really hard to keep it on the DL.I don't see things but when i listen to music sometimes i hear my name in the background.But i know this is crazy so i keep it from my family.Also I've been doing a lot more attention grabbing things around my dad lately,like i'll just engage in conversation or I'll poke him,anything to get his attention.That might not be that weird but i used to be very independent and self satisfying.to sum it up,i feel like I'm turning into a different person or something.Last thing,I used to be able to think on things for ever,hours at a time and just sit and think,but now I'm getting bored with things really fast.Like ADD or something.Please help.