I havn't worn my glasses in about a year?

I'm farsighted, I went to the eye doc about two years ago complaining of headaches and slightly blurred vision. He gave me a pair of prescription glasses, I wore them for a few months all the time, and I was fine, but I got annoyed with them and slowly stopped. I haven't worn them sense. Now I've been studying more, on my computer more, and my head aches are back worse than before. If I look at a computer screen for 15 mins my heads splitting, so eventually I figured I should probably be wearing my glasses.

I don't remember if the doctor said I should wear them all the time or not, and if I keep them on after I'm finished reading or whatever and I'm looking at further distances I can feel a little headache. I don't know if I've just irritated my eyes and head so they are extra sensitive or if I should take them off immediately after reading, etc.. The glasses aren't very strong at all, and my eyes required the right lenses to be stronger than the left. That's all I remember. Do I wear them all the time or is that bad? Have I made my vision worse by not wearing them for this long?