Sexual dysfunction few days after having taken Finasteride, is this normal?

Finasteride has side effects that might cause sexual dysfunction. When you stop taking it the side effects will go away as well.

This needs an in-person evaluation. I suggest seeing a hair loss expert now to go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

One commonly reported side effect associated  with finasteride use is decreased libido. It is in the realm of 1% of male users.  If you are experiencing low sex drive with finasteride stop the medication and the side effects should resolve within a few days. Recent studies have demonstrated that there is not clear evidence of a negative effect of finasteride on erectile dysfunction.  As for ejaculatory volume, a reduction has been established in a small number of men using it with no effect on fertility or sperm count. 

Thank you for the post. While you just started taking Finasteride, this can be a potential sideffect from this medication. The question is, have you had any difficulties in the past? If the answer is no, it can either be psychological or due to the medication. Some clients develop earlier side-effects, others can take upwards to 2 to 3 months. You have other options as well to consider such as Topical Minoxidil Topical Finasteride and PRP, Platelet Rich Plasma. Speak with your prescribing provider. Hope this helps a bit. 

Great question. I have seen similar issues in a very, very few of my patients. I will suggest you to stop the medication and schedule an app with the doctor that prescribe 1.25 mgs as soon you can.
Good luck.