The following is based on my experience in playing over 250+ ranked adventure games and collaborating with convoy mates and opponents for input:
Even during your 10 "qualifying" matches you are still winning/losing ranking points (you just don't see it in game). If you lose all 10 of your qualifying games, you could be at say negative 500 points and it may take you a while to get back into the positives and start gaining ranking because each loss will send you further negative and each win will bring you closer back to positive. Also keep in mind, if you won 5 and lost 5 of your qualifying games you may be close to 0, if you won 10 and lost 0 you would probably already be at around rank 17 and be well on your way with a positive score.
If you quit, abandon or disconnect (even if it wasn't your fault) from any of those "qualifying" games you probably got penalized even more and lost a greater amount of points than if you had finished the match, therefore it will take an even greater amount of wins to get back to a positive ranking points. Also keep in mind if you quit, abandon, or disconnect from a qualifying match then it doesn't count toward a completed qualifying match and that is one more game you had to play because it takes 10 matches fully completed to finish your qualifying and to get a rank score. If you quit a lot you could in theory have 20 losses and still not be qualified because you didn't fully finish 10 matches and you would be in an extremely deep hole that you will have to dig yourself out of.
The good news is that if you are negative you should lose less points for a loss (unless you quit a match early and get the abandonment penalty) and you should win more points for a win. The amount you win or lose is based on both your individual Rank Score and overall Team Skill Rank (at the very start of a game it will show Team Skill Rank and a number under your Team Red or Team Blue name (unless you enter as an Adventure Team of a full 6 person Convoy, where it will then display your actual team name rather than Blue or Red, this is also how you get your team to the ranking leader board, by completing a game as an actual team with no random players), this only occurs on the first screen at the start of a match and you don't actually get to see your opponents Team Skill Rank, but you can somewhat infer what theirs is based on their individual rank scores, except that the guys still qualifying wont actually display their current rank score till they finish their qualifying matches). If you are on a strong team the number will be higher, if you play against a weak team you will be awarded less points. You can even be on a losing team and still gain points if the opposite team has a significantly higher skill point total.