Nofap in relationship

Hi guys, I'm brand new here. Literally like a minute ago. I started my Nofap journey on 19th April. My birthday was on the 10th, I turned 30 and figured I'd do a month as a sort of milestone. Never knowing what nofap was. Also quit smoking at around the same time. Anyway I have been masturbating to porn for longer than I can even remember. Maybe since 13... i used the death grip and I masturbated frequently like up to 3/4 a day sometimes. The most out there content I ever watched was transwoman open but not frequently it wasn't a "thing". Anyway while on this journey I have had sex once with my girlfriend and it was amazing, I felt like my natural sensation was returning because I had kinda been desensitized after all those years of faping and I also used to last forever and not ejaculate. No problem with erections whatsoever... fast forward to a couple of days ago, unfortunately I relapsed. Fapd to open for 2 days. 1 night time session and 1 in the morning. But stopped after that. The same night my penis couldn't get hard and this is like day 4 of my flatline. I get morning wood but like 75% what I used to be. The problem is my girlfriend has no idea what I'm going thru and she wants to link up tonight and probably have sex. I haven't told her because I haven't had the chance, we haven't been face to face since this all began. Tonight is our 3 month anniversary and I hate that htiseverything has all coincided now but I just ahvethought to tell her. The crappy thing is that I love her a lot and she's been sob horny nadaf wanted tonight to be super special. I've been suffering alone, this whole journey I've been having extreme withdrawal from porn which messed with my pre existing depression and also brought on terrible anxiety which I've never had. Today is the best I've felt all week.

Anyway long story short what should I tell her, how do I tell her even? And then how long will my flatline last and once it's gone can I continue having sex till ejaculation or should I take a couple of months off sex completely. I am totally unsure about any of these details. Please any help anyone can give me will be deeply appreciated. I'm kinda at the end of my rope. Please whoever reads this can you help me forward it to whoever might have the best input. Thanks.