Solo Or Duo HelP

I'm having a hard time. When i go on Rank I don't want to go alone, but when i Duo i lose 75% more of my games then i do Solo wise. What's better duo or solo? because in duo i feel a lot less at easy knowing i have someone to back me up. But in Solo i feel pressured and do better.

for Example in this Duo: in this game i was super fed but could not carry my team to victory and I felt like i threw this game http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1910078562/227948380

in solo wise: In This game I was by myself and I ended up getting fed and we won the game. http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1892054054/227948380?tab=overview

But I always thought playing Solo was a bad idea in rank especially if i just started like a couple of months ago. So what's betters Solo or Duo