Hello to anyone who reads this. I need help desperately.
I had, as of 2 days ago, celebrated my longest streak in 5 months-17 days. After a horrible turn of events, I have watched porn 15 times in the last 48 hours alone. Never have I felt so powerless and horrible.
I NEED HELP!
PLEASE, help me beat this yetzer hara with any advice or tools you can give me. I am at such a loss and cannot stop!
PLEASE HELP!

You asked for help. You’re already stopping. 

Hey Sicario Warrior,
It's great that you had your longest streak, that shows improvement and that you want to grow. I would like to help you the best that i can. I can be reached either by email 360gye@gmail.com or you can private message me. 

Sicario

I find that when I fall, I fall really badly.
It is a trick of the Yetzer Hara...it tells you that because you fell, there is nothing to lose by falling again.

I suggest that you tell yourself " I will stay clean" rather than " I will not fall."

You then plan ahead...prepare activities to do when you feel lust or low moods.

Walking, reading, study, praying, seeing or speaking to a friend etc.

Sicario all I can say is i relate to your feelings. Many have been helped on this sight. Follow their lead. Use what you learn to help yourself.
Good Luck!!!

Thanks for all the eitzos! Really appreciate it.

Sometimes it's those hardest falls that get us upset enough at ourselves that we finally go ahead with the next step we need in recovery, be it TaphSIC, filters, therapy, SA, whatever...
My longest streak (87 days) was after such a fall & I was absolutely fuming with myself, I actually sat down and wrote a detailed plan of action to stop m*sturbating, complete with the whys whats hows & what ifs, as well as frequent rewards.
Whatever you choose, it should be a ירידה לצורך עלייה, you should have much הצלחה warrior! Knock 'em dead!

I think that's the worst place this addiction can lead to: not relapsing again and again, but the why behind it all: because you, me, we end up feeling like complete garbage. Absolute losers. And we begin to think that trying is pointless. What'll hanging in there, even for just a bit, help? I'm just going to relapse once again. Yeah, it's a given that I'm an evil sinner. Right?
Wrong!!! Nothing's a given! The yetzer is a master at bringing us to this point of wallowing in regret and guilt. Forget all of that. It's n the past. You're a new man now. Have you relapsed? Pick yourself back up. You fell, and that's it. It's in the past. Get right back into the fight. Don't wallow in negativity. That's all in the past. That's the first step: falling right. If you've fallen, you have to pick yourself up immediately. It's tough, but it's doable. 

Exactly. When one climbs a mountain for a few days and then stumbles into a ditch, it is obvious that although reaching the summit has been delayed a bit, it does not mean he has rolled down to the base and has to start again. While bandaging his wounds, he can enjoy the view, figure out why he fell, and then resume the climb. Similarly, when one slips or falls in his endeavor to stop the negative behaviors of pornography and masturbation, he has not returned to his previous matzav. He should not become me'yuash. He needs to shake off the dust,  celebrate how far he has come, figure out what triggered him, and get back to work. And similar to a mountain climber, he should accept the outstretched hands of support and advice.