The road can seem really, really long. Often the best solution is not to think about it so much and take it a day at a time. Eventually, the streak grows bigger and bigger. I like the idea of small steps and benchmarks.. 1 day, 3 days, 1 week, 2 weeks, 1 month, 3 months, 6 months, 1 year and so on.
Withdrawals and urges will definitely come, I've found the 1st day was fine. Then days 3-7 I had moments of horniness and urges. Right now I'm feeling pretty horny when I'm at home doing nothing. I'm gunning for 2 weeks and that is just the beginning.
It can DEFINITELY be done man. Don't set yourself up for failure by focusing on how long 90 days or 1 year is, it will create all sorts of depression and anxiety.
And you've come to the right place, you'll find a ton of guys in your situation and we're ALL rooting for each other to get it done. If you ever need to calm down I recommend reading other journals and YBOP. That really helps, good luck!!