Pcos+anvulation age 20. Ovulated last cycle on just metformin. This cycle added 50mg Clomid (clomiphene) days 5-9. Chances (in %) of me ovulating this cycle? Next?

Varied. Whether you ovulate is not a matter of chance, but rather a factor of how well your ovaries respond to the clomiphene. If you have pcos, the combination of Clomiphene and metformin are very likely to induce ovulation.

Related Questions

Age 20 w/ pcos+anovulation. Ovulated last cycle on just metformin+provera. Now taking 50mg Clomid (clomiphene) cd5-9. Chances of ovulating this cycle? Conceiving?

Different. So having a period does not mean ovulating. Provera (medroxyprogesterone) may cause you to have a period but it will not cause you to ovulate. Metformin can be effective but it not usually as good as clomid. If you ovulate about a 20-25% chance of conceiving as long as there is no other contributing factor to infertility.
Varies. About 75% of women with pcos will ovulate with clomid (clomiphene). About 75% of them will conceive with in the first 4 cycles. Some of the others will eventually conceive if they continue to ovulate with the clomid (clomiphene).

I have pcos and am on Clomid (clomiphene) and metformin. Is there any reason for a blood progesterone to come back positive if you haven't actually ovulated?

None. Except if you are supplementing Progesterone somehow.
No. The Progesterone level only rises after ovulation. It remains elevated after conception occurs. The only other reasons to have an elevated Progesterone level is from taking supplemental Progesterone or from abnormal endogenous production such as a tumor. It would be exceedingly rare to have a tumor that produces progesterone, but possible.