Sure sounds like time to adjust the bottom bracket!
One thing you want to avoid is making indents that are too close together. If this is your first adjustment, you have nothing to worry about! But what I have started doing to be careful: I pull one screw all the way out so I can look down the hole and see the shell and the existing indents. When I rotate the shell to tighten the chain, I look to see if there is an existing hole nearby. If so, I will loosen the chain a touch more, either to hit the existing hole in the middle or to move further away from the existing hole so there is no danger of overlap. I will first tighten the screw that I left in, watching down the empty hole to make sure I am hitting where I want to be: there should be matching indents tracking the two screws, so looking at one track should let me position the other screw where I want it relative to its track. Once I have got the first screw tight enough to keep things from drifting, then I put back the second screw and tighten it down too.
Of course, don't get the chain too tight. Things should turn freely without stressing the bearings.
I think I have done this three times so far, so I am far from any kind of expert!
But really, your first adjustment at 1800 miles! I had at least two adjustments by then! What chain are you using?
