frequent erection and small penis

i've got frequent erections and my penis becomes tiny when i masturbate

i could see a nerve on my penis all the way from the testicles till the tip of penis. -- i hav foreskin...

i get morning erection and healthy .....

and i reach the orgasm within an minute when my penis is rock hard.

is this is a serious problem?
will i be able to satisfy my girlfriend?
can i hav kids?
cos i ejacualte very early but easily get erection with just thinkin of my girlfriend nude..

kindly help

thanks
--akonrodeo