Is 2.88 mbps, ping 15 ms, upload speed 0.95 mbps fast enough?

I feel that is relatively slow and my internet has been slowing down recently. I cannot fully load a page as it only loads halfway and I cannot watch any video without it buffering. I even can't play a full game on Xbox LIVE without seeing one lag spike. When I do lag on XBL, it's not the host but me. It's clearly me because I'm the only one with 1 bar. It's really been frustrating with my laggy connection; I was on the brink of breaking my headset and controller. I have AT&T U-Verse. Can anyone help me?