Hello dear 

Yes sure you can give it another try, there is no restriction for that. But go ahead with this step if and only if you are that confident that you can definitely crack the examination and get a seat for mbbs. Else, if you are unable to do so, for any reason, don't get discouraged. You still have the option of private colleges, although the fees will be very high. Having a passion is good, but it should be high enough so that you achieve your goal. If you will put in more efforts than you already did, then go for it, else if you think that your efforts were enough but you didn't get a good score, then don't opt for taking a drop. Think and choose carefully. 

I hope this helps you. Feel free to ask any other queries.