Nar not doomed in my opinion.
Thing is, you have to now be quite sensible about your situation. Universities understand that it can often be very difficult to get experience, especially cos of age limits and space and administrative issues etc
What experiences u do have however, make sure u can reflect upon in any way you can.
Then in my opinion, the best way to make up for lack of work experience is to do alot of research into medicine, and care related stuff. By doing this, you are making sure to yourself, and to interviewers , that you have a REALISTIC view of medicine and know what ur in for.
Being able to reflect upon what you have researched is important, and even more so due to lack of experience.
Assuming the academic side of your application is fine, then no your not doomed, just make sure you make yourself stronger in your other areas.
And in desperation...DO NOT LIE, cos its well tempting , especialy when u think ur doomed.
Good luck, Marc