I'm 5'7, 155-160 lbs, 8-10% body fat.
Here are some tips for fellow short men:
1) Work out.
OP, being 123 lbs is not masculine. Height isn't as important as your total presence. If you are in peak physical condition, your height becomes even less of an issue. Eat healthy and lift weights. at 5'6, you should strive to be at least 145 lbs. Don't overdo it though... if you are ectomorph like me, you can literally add as much muscle to your frame as you want, because you'll never look like a meatheat. If you have a naturally thicker build, go for the lean look (swimmer / sprinter).
2) Accept your height.
It is not going to change. The sooner you get past this, the sooner everyone else will. This is not just about women, height affects your career as well. If you can be the dominant personality in every room you go to, you will have more success. Don't project a Napoleon Complex. I cannot stress this enough. Alpha behavior is about being cool and confident. Make eye contact with people. Speak with conviction. Have a firm handshake. Make sure they know that despite your height, you are still present and in control.
3) Learn to beat the **** tests
Both men and women will **** test you for your height. Women typically **** test you about your height on the first date. I've found that women within 3-4" of your height **** test the most. They have to see how comfortable you will be with them being your height or taller with heels. The correct way to beat her **** test when she makes a height comment ("we are the same height!") is to look at her with a smirk and just say "alright." Women have this sick image in their head where their actual height is when they wear their favorite heels. If she asks what your height is, don't lie. Just say your height and change the subject. Don't argue with her about it. Don't get mad. Just keep a smirk and move on. Don't let her hang up deter you from your goal.
99% of the time, a woman being obsessed with your height is her insecurity. Let it remain as such.
4) Give yourself some extra height
Don't go overboard with this. I tried the lifts but didn't like them at all. If you live in a colder climate, you can get away with wearing boots often. Wear boots at the club. Height is more important in night game than day game. A good pair of boots will give you 1-1.5" and you won't have to walk awkwardly (the problem with lifts). In day game, being short can work to your advantage. Women are usually quite impressed with shorter men that display alpha behavior, because it is rare. If you can cold approach a taller woman, you'd be surprised at the results. I banged a 6' chick last week that I approached in day game. The fact that you are approaching her really is an impressive display of confidence (a man's most attractive feature).
For online dating, lie about your height. Add 2" to your profile. Women don't care about your height after you **** them. Don't get in a hiccup about the "ethics" of this. You aren't having any less sex by lying about your height on your profile. Chart:
5'4 ---> 5'6
5'7 ---> 5'9
5'10 ----> 6'
6' ----> 6'2
6'2 ----> 6'3
6'5 ----> 6'3