You should be candid with them that you're uncomfortable with the cash portion of your comp.

5% is an unusually high % of equity, the founders likely assumed you were happy to trade-off cash for equity. Series A is usually a dilutive round and it's normal to grant people like yourself more options to compensate for the dilution (i.e. to keep you at 5% of the new cap table).

My 2¢: I know people in your position who have ~$200k cash comp in addition to meaningful equity. Don't feel bad about asking for more cash, if your founders have a good relationship with you and you're providing value for the company, they'd rather invest the marginal cash in you and keep you happy + comfortable.