540 - 1st GMAT attempt with 2 weeks of studying

Total 540 - AWA 5.5; IR 3; Q37; V27

Hi to everyone reading this, I'm only writing to this for future applicants with the same situation as me, take it as an advice of some sort.

Short review of my profile as an applicant: 23 years old, from Georgia (the country), been working since first year in university (work exp. 4+ years, but not no amazing positions or an owner of some start up etc., mostly being an assistant, IT PM, and digital marketer), due to work had to sacrifice my attendance points at the university so my GPA is 2.88. After finishing university I bought an apartment so all my savings went into that and even though I wanted to study abroad there'd no way for me to finance myself. So I thought the only way that I'd interest any university into accepting and financing me would be via GMAT and TOEFL scores.

TOEFL experience: I didn't study anything, nor have I ever been tutored in English. I taught myself the language when I was in sixth grade and have been upgrading my knowledge since. The thing was right on the day of my exam I got influenza and 39 degree fever still didn't want to miss the exam cause it costs so much. Unfortunately I scored only 107 with the lowest 25 & 25 in speaking and writing, don't know if it's good enough or not but don't plan on retaking one. Will do take advice though.

GMAT experience: Now with GMAT I didn't have any money to waste so before starting I researched and knew that I shouldn't waste MBA first 2 free tests. So I only wrote one and got 480, CONSIDERING I didn't even remember how to calculate 8*7 and no I'm not kidding, the score was higher than I could imagine
My only studying resource was GMATCLUB.COM nothing else honestly since I could barely afford the exam itself. But it was naive of me to expect to improve my math in 3 weeks and that I knew GMAT English. I started reading math topics theories and then doing the problems. I moved from topic to topic like this

1. First mistake was that I only concentrated on difficult problems, and didn't do any of the sub 600 cause I thought I'd automatically be able to handle them after 700 lvl. problems. That was a huge NOPE. Not only did it take huge amounts of time cause I concentrated on: Probability, Combinatorics, Mixtures, Work/Rate, Speed/Distance problems, but also I didn't take into account that these type of problems would be a minority at the actual exams, nor the fact that I'm not mathematically inclined so even the easiest problems from algebra or arithmetic would be difficult for me to solve.
2. I didn't bother to learn the grammar rules, since in CR and RC I almost never really made mistakes thought that I'd somehow would get by. but obviously I didn't.
3. Before the exam day was studying until 1am, which was a stupid thing to do, and didn't get enough sleep;
4. Saw here to eat something light for the breakfast and take some snacks at the exam center, did just that but after finishing quant. I was so hungry when I got back from the break my head was spinning when I looked at the verbal section, so my advice would be to have GOOD breakfast
5. The legend that the score varies 50 points from mock to actual exam didn't turn to be the truth for me. I took MBA.com's second exam the day before and got 530 and on the actual exam, yesterday, got 540 (37Q (I got only 2 questions from the topics I had covered ), 27V), so mocks are pretty damn accurate.

My plan now: since I've got time to submit my GMAT score until 1st April, I'm very short in time to get MY ideal 650 for Amsterdam Business School. I plan to continue learning from this AMAZING platform, since I think it's more than enough to tutor yourself for the exam thanks to the amazing community here.
This time around I'll start math from the very beginning but will include every level question and will take my time to get used to them and not hurry onto the next one, same for the grammar. BUT I don't know if I'm on the right track so if anyone could give me some advice on what to do from here on I'd be very thankful