15 years old sudden loss of libido, erection frequency and hardness

Alright to start off im 15 years old. I dont need to hear the "you shouldnt be having sex anyway" line. I'm 5'10'' 185 lbs, i exercise regularly and am in good overall health. My problem started about a week ago last thursday. Me and my girlfriend have sex pretty frequently   3-4 times a week (sometimes more or less)  for the past few months now. I've always been able to get hard and ejaculate 5+ times a day i typically last about 15-20 minutes. In this last week however (8-10 days) i have generally lost alot of interest in sex, when i do get hard my erections are alot weaker (60-70% of their max give or take) i also am getting hard alot less or not all during the day unless im with my girlfriend ALSO, while having sex i feel i ejaculate alot quicker then previously before (5-10 minutes now). I feel no pain when ejaculating,  a normal amount of semen comes out when i do. I feel as if sometimes  mentally i want to have sex but physically my erections are no where near as frequent or strong as they once were (as little as a week ago). Last week prior to my problem i did experience some slight testicular ache in my right testicle and a dull ache in my pubic region but both of those have since gone away. im verry worried at this young age that i wont recover or be able to perform to my fullest anymore.

[radric]

also i lift weights pretty frequently (3 times a week) and the only other important info i can think of is  i get alot of good sleep (8-10 hours a night) i take a multivitamin and im trying to drink more water.  and sometimes when i pee its in a split stream but theres no pain or discomfort.

[ni2]

i am 27 year of age and i lost my interest  in sex when i grab my penis its not getting hard during masterbate and when erection .iam very depressed with my problem plz help me