Second day on Propecia/finasteride. I'm feeling exhausted, dizzy, and anxious almost like I'm hungover. Is this from the drug?

Although this is not a common side effect of finasteride/propecia, everyone is unique and may react differently to medications. I recommend discussing this with your doctor. In general, finasteride is a well-tolerated medication for most patients. For my patient's who do experience a side effect with finasteride, I have them stop the medication. Once the side effect goes away, we consider restarting the medication at a lower dose. If tolerated, the dose can be slowly increased. Best to discuss with with your doctor. 

It's unlikely this is due to your propecia/finasteride, but I recommend following up with your Doctor. There are great non-invasive alternatives like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

When it comes to medications, countless numbers of side effects are possible, it just comes down to the chances or probability of the patient's symptom being related to the drug or not. The symptom you describe is not common, although a link is still possible. You may want to speak to your prescriber to discuss how best to proceed in your case. He or she knows all your details and may have better insight into appropriate course of action than the internet can provide.In general though, patients of mine who experience similar side effects are encouraged to stop, make sure the stated symptom they have fully disappears, and then restart. Depending on the specific symptom the patient is describing to me, we might start at 0.25 mg and them slowly work up to 0.5 mg and then slowly work up to 1 mg. This gives us both a better understanding of whether or not their symptom is related or not and if it has a dose dependent response. Please discuss with your physician.