I was so stoked to have 30 days clean and sober! I really tried this time and felt like I gave it my all. Unfortunately yesterday I started obsessing on it and couldn’t get it out of my head. I picked up some Fetti and meth. I feel like I’ll never get this. Idk what the heck is wrong with me.
The first 120 days are the hardest part of getting sober. You have the biggest fight of your life. You must take control of your life and keep your eyes on the prize 
Flush the drugs. Flush whatever you have left. If you can do that, you will be saving yourself from all the darkness that stuff brings into you and your life. I only say this from experience. I had a relapse 3+yrs ago on meth, than the real struggle came. The alcohol took control. I had to quit all of it cold turkey with the help of some anxiety medications and antidepressants. It's. Been over 2yrs now and I'm telling you my friend that life doesn't go away but it does get drastically better. You gotta find peace with yourself. When you make the clear decision that you want peace you will get sober. I'm sorry if I ranted. I still struggle but today I woke up sober but with a heck of a tooth ache.
How about reaching out to a rehab program? Let’s get you some help Alex 
You have a mental and physical addiction. You can’t get sober alone. Get into a program that holds you accountable and do whatever is required. I know it’s scary but you need to surrender to survive.
It's often a process of relapse, reflect, regroup. Ya get back up and try again. ODAAT
The problem is that you keep on believing the big lie; that this time, everything will be okay. But it never is, is it? When you pick up again, you get that feeling that comes from getting high and you feel good for awhile. But when it's all over with, you're right back where you started. Now you're carrying around more shame and guilt and have to start all over again.
It’s important to identify your triggers in order to avoid them and reduce the risk and intensity of cravings.
The Cravings do go away and they get further and further apart. But you have to actually not use when you're getting the cravings. You have to understand that it's a big fat lie.
Do you have phone numbers of addicts who have long term sobriety? Do you actually use them before you pick up?
Do you have a 12-step program in place? Do you actually go to meetings? Do you have a sponsor? Are you on any of the steps?
If you're doing this on shear willpower, I wish you a lot of luck.
Drinking and/or drugs is but a symptom of our problem. We have to get down to causes and conditions.
You might be an addict with no self control concerning drugs and alcohol. I suggest you try meetings. It worked for me.