Hey

I'm 5"9, 124lbs with 8% bf.

Used to be 167lbs with 21% bf.

Is it possible for me to get to something like 155lbs with 10% bf ?

I know it may take months...but do you think it's a relaistic goal?

Thats a very relaistic goal. I am right at the same stats you are now and everything I read says you can make it to how big you want you just have to keep working out hard.

It sounds realistic to me, as long as you eat and exercise properly.

This time I am gonna work hard and watch very carefully what I eat.

I think I'm gonna keep track on my girth every month while setting myself goals each program I do.

It should help me keep pushing myself to the limit.

I've been bulking for 5 months - my average gains are 0.5 pounds per week.
body fat % hasn't changed since I started. so I think it is safe to say I am not quite eating enough... I think there should be some fat gain while bulking - that confirms you are always at a calorie surplus.

Anyway - I am ok with slow clean bulking with little or no fat gain - but if you want to get maximum gains - make sure you are eating enough.

It is possible, but will take some time. How fast did you loose the 43 pounds before? Seems like maybe you over did it a little bit, but that may bee good news for where you are at now. You lost 26 pounds of fat, but also 17 pounds ao lean mass. It should be easier to regain that lean mass than had you never had it. What you are wanting is to add 31 pounds with no more than 5 more pounds of fat. Looking at John's bulk last fall, he gained 15 pounds and went from 8% to 11% in about 2.5 months. This seems like a fairly good bulk, some could do better, some could do worse. But you should expect it to take at least 4 to 6 months. And be careful not to over do it. Some of those 17 lean pounds from before could really help you now. I would probably plan on stopping in 3 months starting a mantenance phase, and checking your progress. See if you need to throw in a small cut. Set a value, 12 or 15, or something an be sure that you don't go back above that percent. You have already proven your dedication, now lift hard and eat more. Good luck.

I have lost some muscle, but I think that the big part of the weight I lost was which was not fat, was water.

I think that since I am using the same weights I have used when I started, and I even grew stronger in some excersizes.

I lost my 40lbs in 4 months.

About 2.5lbs per week.

I was using 50/30/20 (proteins,carb,fat) with about 1200-1400 Calories.
Doing Cardio 5 times a week, and 4 times weight lifting.

What do you think I should eat in order to slowly bulk without gaining extra fat?
(40/40/20 ? , how much calories?)
I'm gonna do cardio for like twice a week

most of your questions are addressed here:

bulking guide (http://forums.johnstonefitness.com/showthread.php?t=51)