The plain truth of the matter is that not everybody is meant to be a salesperson.
If there has really been no measurable improvement in your numbers (as compared to your colleagues) then you might have to just face the fact that sales is not a good fit for you.
3 months is a pretty decent amount of time for your supervisor to have given you, objectively speaking.
Perhaps the reason for your not having shown more initiative to improve is that you just plain don’t like the whole process of garnering sales.
There was a period of time in my life when I was taking a series of sales jobs temporarily just to get by until I could get back to teaching.
And I eventually came to the point where I just had to face the fact that even tho I was pretty good at sales (I was never fired but I often quit and moved to a different product) I just did not like sales. It just wasn’t a good fit for me. No matter what I tried, it just wasn’t exciting or rewarding for me, even tho I was having some amount of success at it.
So, only you can decide whether this is true for you. I’m guessing this may be the case because you’re almost at the end of this 12 week period and haven’t shown much initiative on your own to make whatever changes were necessary (or to even find out HOW to make those changes.
That would suggest to me that you have little enthusiasm for sales but might very well blossom in some other type of endeavor. Sales can be a very discouraging way to make a living if you’re not loving it because there is a goodly amount of rejection that just automatically comes with the territory.
Someone who is a born salesperson has the attitude that it may take ten NOs to get to that one YES, so let’s get them out of the way as fast as possible.
Someone who is not a natural salesperson dreads every single NO that they encounter and it just discourages them further.
Try to honestly assess yourself as to which of these two best describes you. If it’s the second, then find something else rewarding ASAP.
Perhaps your supervisor is doing you a kindness to to bring this to light so that no more time is wasted in a fruitless endeavor.
Perhaps she may be able to give you some insight into what may be a better fit for you.