Talk to your superior when you get enlisted.
Or sound off at CMPB when you are registering/medical checkups.
Directly ask them for suitable arrangement if possible. If you are
deemed to be able to stay in then suck thumb serve the country.
No matter what there will be a way out and SAF will not ill
treat you. Most importantly is sound off. LIke what Rednano have
posted, if you are required to stay then you can request for
financial aids.
Cheers, not to worry too much. =D