ive been 5'9 at 120-135 lbs for a while. One thing i can tell you in order to gain weight you have to eatttt!! 2 meals a day just istnt gonna do it buddy..theres a few appetite stimulators out there never used any but you can give it a try...another thing is to sign up for the gymm. who care what other people think they probably started out just as small as you are too. i see people at the gym skinnier than me n see them try so hard and its funny but ive been in that position before so i know how it feels. theres this one guy at the gymm very skinny hes been goin for the past 3 months and ive noticed him make lots of progress. he walks around with a sheet with his daily excersices and writes what he does. pretty much you have to start somewhere.....even if your considering juice you would still have to go to the gym and work out...dont worry about the amount of weight your doing just focus on proper form and youll see results. you could consider epi which is what im currently on but i would reccommend that at least 6-12 months into your training...so far ive gained 8 lbs in 3 weeks but if you are planing on using epi please do the research on the site because its more than just popping a few pills and working out...you need a proper post cycle and much more...everything in short
EAT EAT EAT
Start Training Hard!!
Drink Protien At Lease 120g a day
Creatine After Working Out
And you should see great results naturally