Ranked LP gain and loss

So I finally decided to play ranked after a couple of years playing league and ran into a very rage-inducing issue right after I started. The firs time I tried playing ranked I didn't really pay attention to LP but I stopped instantly because of how toxic people in Bronze where, but this time I decided to just start playing and see how high I can get until the season ends, now I instantly got into a winning streak with Taric and Syndra , but once I passed to Bronze IV I started loosing some and winning some. I thought that keeping my amount of wins just a bit higher that loses would get me to the next rank but that's when this happened, win (+13 to 16LP) and loss (around +21LP) so by loosing a single game I would get punished to the point of loosing points for almost two full victories? I kept going just to see if this was because I hadn't played ranked in ages but it still hasn't changed, honestly if this isn't a bug then it needs to be changed, I know the system is made to keep player in ranks they are meant for but at least give us some motivation to keep trying after loosing one. I'm going to continue looking on info about this to see what its all about, but I can assure you I won't be playing ranked over 1 match a day until this changes. I'm fine loosing point when I loose fair and square but on bronze at least half of your losses will surely be because someone disconnected or simply never joined, not to mention having to face-off against smurfs -_-

EDIT: again, I just won three games in a row (starting from 0 LP going to 33LP) and then after loosing a single match I loose 21 LP, how is that fair in any way?