You may not be stringing your racquet enough. If you're using synthetic gut, then the rule of thumb is you should be restringing per year as often as you play per week.
Example: if you play three times per week, then you should re-string three times per year.
but that's absolutely minimum. If you want to maximize the performance of your strings, then you should restring more often that that.
If you're using poly, then you should be restringing after about 10 to 15 hours of play time on those strings.
Bottom line is, your strings are way dead. so far dead that it's not even funny. You should restring, and quickly at that.
Playing on dead strings definitely has its limitations. You lose control, feel, and often they become too powerful to control.
If your issue truly is just to get a new string job, then yes you will see a performance improvement. But its really hard to say for sure.
If after you've gotten your strings redone and you're still experiencing the same issues, then you can do one of two things:
1.) post video of yourself playing to the "Tennis Tips" section here, and let some of our wiser contributors give you some advice.
2.) see a local teaching pro in your area.