assuming you are talking about HIV medications.... your genotype/phenotype ('resistance test') likely showed your virus was sensitive to the medications your doctor started you on.... however, if you keep missing doses as you currently do, you will certainly develop resistance to one or more of the medications in your regimen. the best scenario in that case is that you will no longer be able to take just that medication you have become resistant to. the worst case scenario is that the mutations you develop will preclude use of several medications in that class of antivirals.... and over time you will run out of options.
the rule is... if you're going to take antiretrovirals to treat HIV, you need to make them religion. missing doses is not ok. if you're going to skip doses, you may as well stop the meds altogether so that you will avoid development of resistance. of course, if you stop all meds, you also risk damaging your immune status. that is the central conflict in treating HIV.... long-term side effects of medications vs. potential damage to the immune system from not taking them (or taking them incorrectly).