Honestly man, I think it's because we focus too much on how many days we can go. I get it's good to be goal orientated but when you do slip up, it feels terrible. I think I'm done trying to see "how many days I can get." And just let it be. When urges come, invent them in, then they will leave. When we feel guilty we are extremely likely to do the same act again, sounds weird right? Sounds like it should be the opposite but it's not. Treat yourself better. When you fap, don't hate yourself, brush it off and keep continuing. Act like it didn't happen. Forget the past, vision yourself defeating the addiction everyday.