A lot more people are mining now and their miners are getting faster and faster. Difficulty has increased a lot over the last 6 months.
https://blockchain.info/charts/difficulty has anything changed in the last 6 months that would require me to change my setup? maybe just the amount of people mining has drastically increased since the prices went up(dropping reward amounts)? I was getting 0.01btc/day just six months ago when mining between 0.25-0.5Ghash/sec between day and night... now I'm not even getting 0.001btc/day mining at that rate.