I also have multiple diagnoses, and take a large number of different medications every day. Over the years, I have developed an excellent working relationship with my pharmacist. He has all my prescriptions on file in the pharmacy (on computer), and once a week I go in and pick up a Webster Pack, in which my pharmacist has put all the medications I take in one week, labelling them 'morning' 'lunchtime' etc. and the dates on which I should take them. If my doctor(s) change my medication, then I notify my pharmacist and he changes his records accordingly.
The pharmacist also tells me, when I go in to pick up the Webster Pack, what medications I am running low on, so I can ask for new prescriptions when I see my doctor(s) next. This is not only a brilliant solution when travelling, but cuts out much of the stress and anxiety of counting out medications yourself. I am writing from Melbourne, Australia, so I do not know whether this service is available in your country, but there is no harm in asking! @ellu