serious problem please help?!

I went to the Doctor yesterday and she told me I had a upper respiratory infection and a cough so she prescribed me a Z-pack (anti-biotic) tussionex with hydrocodone and an inhaler Ventolin could any of those be causing my problems, during intercourse I keep an erection but as soon as I pull out I lose it and I feel no urge to ejaculate last night we tried for over 2hours and again this morning and nothing.