Sexual health

Patient: Hi im 21 years old and i have a problem mainting a erection or only get semi hard not enougth to have sex with my girlfreind, I think this might be down to be being nervous and over thinking about getting a erection instead of relaxing and letting it happen naturaly, anyways i bought ( original blue pill – double strengh ) and it says on the back of the box if you have any heart condition seek advice from a doctor first, I have a slight heart murmor from when i was a child had no surgery or problems ever doesnt effect me from doing anything i have a hospital check up every 3 years and its always been postive news, if i take this pill will i be safe, is it okay with alcohol im aware it will less the effect just as long as it doesnt effect my health.