What is reality?

For the last 6 months I have been having great difficulty knowing what reality is. If I imagine something I can see it happen, like if the house is on fire, I can see and hear it. I can imagine 2 random people talking to each other, and it will appear right infront of me. I see all this stuff happening around me, but to me it just seems so... normal? So in other words, im having trouble knowing what reality is and whats just my imagination. People have told me that I have been jumbling my words up and talking about wierd things. One time I remember someone was asking how I was and I said 'im feeling so great I can tell the photo on the wall has a headache.'
i dont hear random voices saying bad things to me like a schizophrenic would. I just see and hear everyday stuff, like a plane in the sky. Nothing scary, which I feel is worse because I cant tell. I listen to music in headphones on the bus and I have been told I sing out loud without realising it. It feels as if the normal thinking voice is too loud in my head and I cant tell if its my actual voice or my thoughts...

what do I do?
What do I have?
What do I need?

Please give me some advice! Im going round the twist with out even being aware! I dont feel like I have had changes, all this time I thought I was completely normal!