Hi @mak_trouble891, lots of things can affect how long it takes to cum. Yes, medication (lots of antidepressants, for example) can make you less sensitive. Alcohol & other drugs can as well. Psychological issues like stress, anxiety, depression & relationship issues, are all things that commonly get in the way of feeling connected to your body or relaxed enough to be fully aroused. It’s really essential to understand what works for you, ensure there’s enough time for foreplay & be honest about your needs, first to yourself & then to your partner.
For more explanation about how sexual response really works & strategies for improving your experience, check out this really thorough article over on Scarleteen 🙂