My answers would be in parts like your questions
How can I understand her behavior about getting close to someone? I mean when I tell something I want to see some clear line in what to do in the future and where to go to?
Her new beahviour, is either a gentle way to tell you it's over, after the trip with the MALE friend, or she is in the natural/cultural woman delemma, you know there is a natural and cultural woman in every woman, which means than women unlike what they pretend they like sex like we do in not more( thats the natural woman), but the cultural one behave ladylike, tends to make sex after getting to know the guy very well, so she won't be branded as a slut, like she told you in previous discussions together. So I'm not saying she is no more intrested maybe she thinks of you as relationship material guy, it's good to have a relationship qualities but you have to be the one in charge.
Am I doing some serious mistakes I am overlooking?
what I advice you to do is to cut your communication with this girl, you'll text her and tell her that there is many things going on in your life and you'de like to share them after with her. that would be all for the 3 following weeks, you can take risks as you said you won't marry her it's only for practice.
Because if you don't cut communication with her you'll look desperate, and thats a beta male trait, and if your girlfriend brand you with that title, you are no more attractive and that will help her justify in her mind why whe refuse to be with you in the first place and that's the last thing you want to do. The Cut off will show the girl that you are unfazed by the break up which will increase your value in her eyes, in allows you to put your life back together, and it will make her receptive to re-open communication with her after. so the cut-off would last 3 weeks, if she tried to call you ingore her calls ( if she calls you at your work, tell her that you want you to be friends now , and you respect her time and space, if she tells you is it done? tell her I'm not saying we're done, I'm just saying that I need my space too I will talk to you soon. If she came to ur house tell her it was nice to see her and you have to get back to what u were doing.
If she called you like crazy ignore her calls instead text her like this quick message :
"hi ___, just a quick note to say hey and i'll talk to you when I get the chance"
with accomplishing this, you'll be the one on the top, the one on control, and it will help you boost your ego, becuz u r now the one being followed, the girl will try to win you by trying to contact to boost her ego but you'll give her noo chance MAN. During the three weeks you will work on your attraction trigger, ( looks (build muscle if you need to, get a tan, be well groomed ( after 3 weeks you want this girl to notice the diffrence), get a social life, get a hobby of yours, get involved in cooking classes it always got all women class u'll be the only guy, get to know new girls it helps even to go over this girls she will not matter anymore, don't say she's the one, becuz I can assure to you there are out there more girls more intresting than this one and hey you are the SHIT and she doesn't deserve you if she behaves like this)
on the 21ST Day call the girl to go grab a cup of coffee, or call her and tell her that u've been doing cooking classes, and would like her to share a meal with you.
Was it bad to make the escalation in the bed again for the makeout like I did?
Yeah that was lame MAN, you should be taking over the relationship, and boob touching, you are not 14 anymore, you should've ignored her after the make out and not make a big deal of it, put some music on and chill out on the couch, you are having sex with others, and you are not weakned by sex.
I guess in the second answer, I answerd all the reamining questions
Cordially
DMLOVE
PS : by the end of this if you try out you may even laugh at urself, because you crave for getting her back at the first place, and find more other intresting place, and maybe you'll make her know, who makes the decisions in your relationship