Why keep playing? You are not going to get any better until you figure out what you are doing wrong. Just playing and winning sometimes and losing sometimes but never getting better seems rather useless.
Of course I only starting playing chess to get better so this may be part of my issue.
I think wo do get better the more we play.
The silly mistakes we make are merely lapses in concentration or not studying a game sufficiently before making a move.
I sometimes play with one eye on the clock e.g I know I have to go out in 10 minutes say but "lets make a few moves before I go so I'm not confronted with lots of games with 1 day left on time when I re log on"
This is when I make the most mistakes.
Another time is when I do sit and study for ages , find myself going over the same possible moves over and over so think "what the hell, I'll just move".
Finally I believe rating to be a poor measure in general of a players ability because it's only based on current rating.For example you are rated 1500, you lose to a 1200 player so lose lots of points.You look at the opponents stats and see his 5 year rating is 1900 but he's lost a high number of by timeout hence the low rating.