Feeding teemo does not mean you suck by any means. All it means is in that particular game, the teemo did better than you. Everyone can have a bad game and consequentially a good one as well. You can't base how good you are off of one game when people play hundreds to thousands of games depending.
One month in playing about a game or two a day, you aren't expected to be great or even really proficient. There is a bunch to learn in league, from the items, champions and all their abilities, how to last hit, what to do when, how to not fall further behind when losing lane or to turn it around.... the list goes on and on. You can't possibly be held accountable for everything one month in. You should probably be getting a good feel for a couple of roles by now and some more of the common champions that you see.
Don't worry about it, it just takes some time to get it all; luckily, it comes really easy if you pay attention to what's going on and want to improve. Just enjoy the game, it's here for enjoyment and fun :D