I don't understand MMR
So I made it to Gold V after 2 years of struggling through silver. once I got there I thought that I read I couldn't be demoted unless my MMR dropped to Silver V equivalent. So I messed around on Anivia support and lost like 20 games and pretty sure it tanked my MMR. I decided to go back to my good champs, only I noticed when I won games I gained 11 LP and when I lost I'd lose close to 30. So even though I won a lot eventually I got demoted to Silver I. Now my MMR is still garbage I think, only lately I've been getting matched where my teams have been going 0-10 in the first 10 minutes very very consistently. Am I somehow expected to carry these teams in order to improve my MMR? I rarely lose lane and usually end up with the only positive KDA and farm at 20 on my team. I just really don't understand what I'm supposed to do... Make a new account? Are there any tips for improving my MMR? Thanks.