I take clonodine, hydralozine, imdur, diovan, (valsartan) coreg & amolodipine for hbp & levothyroxide for thyroid. how can i keep longer erection & better sex?

Talk to your doc: If you have weak erections inadequate for sex or short duration that does not allow for mutual pleasure, then see what med changes can be made. I assume that you have some major pathology that has put you on these meds at such a young age, so there may not be much wiggle room. Your meds may rule out viagra, (sildenafil) so you might need to resort to vacuum devices.