This involves men's (teen) health? Some one help please!!?

Im 15 years old and suddenly today i didnt get my erections like i used to get. Just yesterday i was perfectly normal and i got my hard erections. Im 6inches erect and 4inches flaccid but now its like 3 inches flaccid and not even thinking about sexual things can get me an erection. I'm hoping this wont affect my life, and that its only a temporanly thing. Like in school i used to get erections for no reason and today i dont.
Latley i have been doing squats for execersie... can that be it why i dont get them no more?
And then i just read that if you do a kegel excersive you can have better orgasms... and i started doing it sunday but then i stoped yesterday because i saw no point in doing that... can that be it as well?

Please can someone help me and try to tell me whats wrong with me??
Thank you

ps: and if i do get an erection it only last for a few seconds unlike the ones i had yes.... not to say anything but i am sexually active with my girlfriend and we do use a condom.

it's fine..you're normal...

ok, u'll be fine. and if your not, then i'll take your place and have sex with your girl utill ur ready.
You sound like a fairly anxious individual and that could be it. As you get older you won't get erections for no reason like you did when you first hit puberty...welcome to adulthood. It is totally normal...it is not caused by exercise or Keigals. If you notice any pain or discharge that isn't normal then you can be worried. I promise that your penis isn't shrinking...chill out and don't be so worried about it.
if you are doing exercise that is the probable reason you are burning your testosterone and believe me the older you get the more control you have of your erections is just a process of growing up. the older you get the more your erections will be control by you or you excitement of being in the near act of sex.
Because your getting it with your GF your more likely not to get the unexpected pop up from johnny trouser snake. Your perfectly normal i had the same thing and it's all part of growing up so relax.
First of all, don't panic. Your mental state has a lot to do with your sexual state. Ask yourself if there's anything going on in your life that's really bothering you. If so, that may be the contributing factor. The other things may be the amount of sleep you get and the amount of exercise. Try jogging for a while and don't do the squats as much. It probably doesn't matter, but give it a try. Lastly, I'm fairly certain this is a temporary situation so don't let it worry you. Worry is the quickest way to stay soft and sad.
Just wait it out. It should be over soon. Its amazing what our peckers put us through throughout our lives. This will pass