Hello.
I can't give you any information without more details.
What anti-depressants are you taking?
How old are you?
Do you have erections upon awakening?
Do you have erections during self-pleasuring?
What situations are you having difficulty in? Only with certain partners, or all the time?
I can't tell you whether your medication is a contributing factor because I'm not your physician and I don't know your history. Prozac CAN interfere with erections, so you might want to check with your prescribing physician to discuss other alternatives. There are several anti-depressants that don't usually interfere with sexual functioning.
The fact that you have erections at other times tell us there may also be an emotional component. Prozac MAY be contributing, but you may also have some other concerns. Ask yourself what has changed in your life and in your relationship in the past year. Stress, anxiety, relationship conflicts, etc. can all interfere with your physical response. To explore this further, see a therapist who is trained to help people talk about sexual concerns. Best of luck to you. Dr. J