I accidentally posted this in another section and I didnt see this section till now but I will re post it here

Hello there, I'm new to UG but I've been using UG over a year just reading through forums and for tabs and I've come along a problem lately. I just bought a new microphone its pretty cheap and I've been recording for almost a year with it and before I could record distortion no problem it was pretty clear and sounded good on songs but as of lately when I record songs, whenever I use any type of distortion to record, it doesn't get picked up like for example If i play a riff it starts off well but then the sound fades away after i play the recording back, its hard to explain but here goes. I Record a riff. When I'm done i play back what i have recorded. The riff starts off fine for the first 5 seconds then just fades away quieter and quieter and I can no longer record anything with distortion. If I try and play it back after recording you can hear the sound just fade away. What can I do to fix this problem? I've tried putting the mic at different angles, up to the amp farther away. I've switched programs from like N Track to Audacity to Mixcraft and that doesn't help. I dont know what the problem is. Could someone help me out?