I haven't been to the gym since Sunday...I'm going tonight but was curious...how long do you have to miss before your body starts to feel the effects of "not training" more so in weight training!

Depends on a lot of factors, both physiological and psychological: your age, fitness level, how hard you have been training...

I workout regularly but have been fatigued this week so I've been putting it off....I'm 40 (hate saying that) 5'5 and 130 lbs...body fat I'm not sure of. I'm very active! but I guess its guilt more than anything and was just wondering what my body is going through having just stopped automatically. Thanks.