Hi
It is far too early for talk of throwing in the towel after only 10 games, you should not be disappointed with your start 5 teams between 2,900 - 4,000 position is decent in a game in which there are at least 126,000+ teams. Things can change very quickly and rapid gains can be made with the right captain changes at the right times, so keep going and be positive and you can still improve on your decent start.
I have been fortunate enough to have had a good start and reached the top 100 with my best team it is now in joint 100th position just off the leaderboard having sneaked onto the bottom before last nights game, and my second best team is in the top 200 as well, as I referred to good calls/striking it lucky on my captain changes have probably made the difference as I started with Rooney as captain in one of these teams and am probably not giving too much away in saying switched him a few games ago to a certain Arsenal striker. The hattrick against Chelsea was an unexpected bonus by the way.
Also be prepared to make bold moves, it can pay off, hopefully I will not regret my decision not to bring in Ba yesterday evening too much.
Looking back on the history of these teams I have probably fielded on average 13 or 14 players most weeks, so don't feel that you have to have all 15 playing each week. I set my teams up early around Man City players, partly because they are good and also in part due to the way their fixtures worked and also looked to Europa league teams to include players from those teams to maximise point scoring opportunities in my squad as there games fall on Sunday.
I hope I am not teaching you to suck eggs here but goalscoring midfielders, identifying midfielders who can score goals over the course of the season and keeping them season long where possible due to the extra points for a midfielder goal over a striker goal means that goalscoring midfielders are worth paying for, although some of them are underpriced

Essentially 12 midfield goals are worth approximately 20 striker goals.
Again, not meaning to teach you to suck eggs again but players from teams that can win games, 3 points for a players team winning keep the points ticking over even if the said player doesn't do much else in a game.
Good luck for the rest of the season with those captain changes and transfers and I am sure you can make progress.