I want them to be very realistic and about the height of my head. My biggest concern is weight, I’m unsure as to what materials to use. I also want the way they are attached to be very discreet and look very natural. I need it to take carving well and be strong enough for my clumsy self not to break by accident. Possibly, and likely going to be hollow in order for minimal weight. Also what paints should I use?
I don't know how "handy" you are but I would suggest Papier-mâché over a simple wire armature. It would be lightweight, fast and inexpensive to make, require minimal tools and be very forgiving of mistakes. For a bit more durability and added texture, add a final layer of simple cheesecloth after the form has been built up. Then paint or stain for the desired effect. Any paints would do – inexpensive watercolors, etc.
As for the form and how to wear them – depends on how large you want the antlers to be (e.g. moose antlers can be huge. Deer antlers smaller, etc.). Perhaps sacrifice a "baseball" type hat to build off of and add a "chin strap" to keep it from slipping off of you head.
What about some sort of wide headband. You could construct the antlers out of some stiff wire (like fencing wire) and wrap them around into a frame. Then you could inject spray-foam into and around the wire, trimming the excess with a knife.
I'm not sure if the headband would be stationary enough; you might have to make some sort of wire "corona" and add an under-the-neck tie strap to hold it down.
I once made a halo for an angel costume by making a wire corona and using wire to hold up a big brass ring behind my head. That worked pretty well. Your antlers would be a bit heavier though, so the tie strap could work.
Or, instead of a headband, you could make some kind of cowl that covered the head and neck and could be tied on. That would support the antlers better, and maybe you could even attach deer ears.
Another idea for the antlers could be to get some really thin, long balloons - use thin wire to shape them, then cover them with latex (don't know if spray-on latex is a thing). Then you could pop the balloons and remove them and fill the latex antlers with cotton. Some thick wire would hold them up and you would attach those wires to your headband or corona.
Actually, you could just use real antlers, in fact. I have lots of them in a box. I get them from my friends when they go hunting. They keep all the big racks but I can get the smaller ones from them.