Surely you should be progressing slowly, not just jumping to a ridiculous weight you can't manage because some **** on TSR who is probably a skinny little weed told you that he lifts 50kg three times a day.
The fitness chart that came with my dumbells (York btw) said you should find a weight that you can lift relatively easily, and do 12 reps. The up the weight slightly and do 10 reps, and then up it again by about the same amount and do 8 reps, then move onto the next exercise. For me this tends to just be adding another wheel onto the bar each time to increase the weight.