Falling MMR/Elo

After having fought my way to get out of bronze and into silver I had several games with trolls who constantly ran down mid/fed. they were frustrating to say the least but I didn't get kicked out of silver and back into bronze. having a few bad games after that I noticed whenever I won a game I gained roughly 13-16lp but losing a game I lost 20-25lp, making climbing extremely difficult. I cant seem to stop losing games, I'm not good enough to completely hard carry a game but I generally do well on average A or A+ personal performance occasional s's even when losing matches. so why does my MMR keep falling making me lose more and more lp per loss when I'm doing well I just cant hard carry.

For example I just won a game as adc with an A+ Lucian, and gained 14lp, and then played kindred jungle finished again with an A+ but losing the match and losing 23lp. I get winning games is a team oriented thing but does personal performance count to nothing towards mmr/elo? Is the only solution to win a streak of games and try get back? when will my lp gains/losses get back to relatively even? it honeslty makes me want to stop playing league its very depressing going 25/2 winning nearly every lane for everyone else just to lose and lose 25lp because my team cant stop feeding/getting caught/being silly etc