Do you have pcos, they gave me metformin for the pcos and i am ovulating earlier and earlier each cycle.
In addition to clomid, there's femara (which is similar to clomid...pills you'd take on CD 3-7 or so), and then of course there are injectables, which are much stronger than clomid and femara. Those all help the follicles grow, and that can often help with a short luteal phase, as well, because it usually leads to higher progesterone levels after O. However, you could also ask for a progesterone supplement to take after O has been confirmed to lengthen the luteal phase.
Is there an RE in your area? If so, I would suggest seeing and RE instead of an ob/gyn. In addition to monitoring your cycles and prescribing more potent fertility drugs (obgyn somtimes prescribe clomid, but never injectables...as far as I know), the RE can also run some tests and make sure everything is OK with both you and your DH.
Best of luck!