I think it is a valid concern. Personally, I still think we are likely to get in a loan stopgap - probably not someone who is going to make every one happy, but cover till the summer.
But if we don't, there's not much more to say other than a) let's hope we don't get injuries to the few forwards/wingers we have (on a side note, I seem to recall a couple of seasons ago that many were touting Watkins record for not getting injured - and then he did almost immediately), and b) let's hope we get more goals from set-pieces, midfield and youngsters. That would obviously be the expectation from Emery and I guess we just have to have confidence in him.
But, yeah, we will obviously be slightly weaker than before the window and there is risk it will bite us. Hopefully this will be irrelevant over the next 24 hours!