Just wait.
There is no special order in which a CO has to work a case, so there is no point in comparing what happens to you with what happens to anybody else, and anyway, no two cases are exactly the same, so what needs to be done can be totally different, even for people who happen to have the same job.
Also, it is common for clerks (not caseworking COs) to look over applications when they first arrive, and to send out for any evidence they see is obviously lacking. What your friend received has not necessarily come from the CO at all - anyone in the office is an 'Immigration Officer'.
Apart from that, when your case is allocated to a CO, it joins the back of his rotating queue of about 100 cases. All COs have to work their allocation of cases in rotation. They take the first, do everything they can for the time (sending out queries, or ticking off replies), then put that to the back and take the next, then the next, then the next, and so on. They don't take any file out of order. So your CO won't even look at your file until it has worked its way up the queue and gets its first turn for his attention.