I have been doing fairly well in my rank games and recently i just won two games one of which game me 14 lp even though i haven't been toxic at all. Then for the next game i win 16 lp. So i go to play another game and yes, i lose and i wind up losing 21 lp and brings all the way back to where ti started in one game. i want to know why i am getting no lp for winning and losing too much lp when i am losing.
That scenario sounds normal
being toxic does not relate to your lp gain or lose at all.
Generally if your in a stale spot (like bouncing between silver 3 to gold 3) and then get a sudden spike in elo the system will class this as an anomaly because it is not normal. It will then try to adjust the lp gain/lost to put you back where you were. While this can seem negative this is also done when going on big lose streaks. this is to help balance for constantly changing factors. For example Im an on hit jungle main, this means (apart from everyone on both teams wanting to rip my nuts off) I play generally 
in that order. However last patch all on hit junglers expect kindread got a huge nerf. This has lead to all the on hit junglers expect kindread having massive loses in winrate for example yi went from about 53% to 47%. Because of factors like this I have gone down in elo from plat 2 promos to plat 1 to nearly being demoted to plat 3 (this might not seem big for you but at higher elos this is like going from gold 5 to silver 5) so this system is helping keep me in my skill range even though factors have made my pool quite weak at the moment. When my champs where strong however I received the treatment you have i was gaining about 8 lp a win and losing up to 35 a lost because i had like a 92% winrate on yi in about 40 games. The reason it does this is to help even out spikes and lessen anomalies. However if you slowly clime over time this will not happen to you because it will not be classed as an anomaly i hope this helps.
