Doesn't seem to be very good conditions for a separation with the intent of reconciliation...mainly med school...as that in itself is going to be such a huge physical and emotional drain on her.
Yet, I know asking someone to put off med school to fix a marriage would probably be asking too much. I would drop something in a heartbeat to save my marriage...I know my STBX would not.
Having said that, I would suggest that you take the time to bring the focus into your areas of responsibility. Do your part to demonstrate your seriousness of fixing things even if your wife isn't presently able.
unblinded made a very good point as to not diminish your perceived value/wife's respect. You do this by perhaps doing a partial 180...because there is still SOME intent to save the relationship, but I would highly suggest you refrain from talking about the future or try to corner your wife into recommitting. Let the cage door be open without any strings attached. I know this feels like insanity because you already aren't spending much time together...but you need a total PR overhaul.
Hit the gym. Start up a whole new network of support. Get a new style going for yourself. Mix it up. And when you do meet with wife, you are basically going to take her on dates where she can feel some release from the stress and pressure of her schooling...and doesn't feel like she is compelled to have to attend to your emotional wants/needs/longings. Again, do not talk about the future...let her bring it up...and when she does, don't spring like a bear trap.
For a person who has one foot out of the door, being pressured repels them. If you leave the cage door open, make yourself more attractive, and give them space...they may get curious and float back on in. That is your best bet to keep her in the game.
However, setting a timeframe and laying down the gauntlet of "enough is enough" is still ultimately justified...as her expectations to drift in this separation limbo without any explicit plans or steps towards reconciliation is not cool. This however, won't be the maneuver of a lesser being, where you are needy and whining for your wife to come back because it is unfair. No, this is you taking power when you have demonstrated attractiveness, self-respect...and has been playing a cool-cat while wooing your wife back. Eventually you will need to express your expectation that this limbo ends...that you deserve better treatment...and you are prepared to dutifully call it quits and move onto bigger and better things.
I guess what I am saying is that you need to get far away from the perspective that you need to measure up to her expectations...but you need to increase your perceived value, so that she will be forced to reckon with your expectations. Not whiny expectations, but expectations from the new, sexual demi-god that you have become during the separation. Changes that are real, not surface...which is hard to do, but necessary to put a jolt in this thing.
That way, if she decided to reconcile...then you can walk into full confidence to dictate for yourself what needs to take place while she has to decide if she'll join you in that direction or not. No compromises. And if she has decided to move on, then you have already done your own steps towards independence. I know it is stressful and lonely right now, but you are going to have to dig deep and get over the rejection your feel to take charge of your life and situation.