HELP! Technical Problem with recording.

Please help!
I’m using:
Cubase Al5.
Cl2 Interface.
SE Electronics Condenser Microphone.

I’m having problems recording vocals. When I play back what I’ve just recorded, here and there the audio is missing. However, if I drag the mono vocal track into an stereo audio file it’s all there!

When I sing, I can hear my voice “double” in the headphones, or as a slight delay perhaps.

I have tried changing the audio driver buffer size, but it doesn’t seem to work.

I’m new to Cubase, and I’ve had this problem since I bought it. Please help! If you need any more information please ask!