Have i screwed up my chances of having a baby?

Hi there.
Really new to this so here goes nothing.
I'm 30 years old. I've been with my partner 13 years and we've put off having a baby for various reasons. "it's not the right time for us" "we can't afford a baby just now" "i've only just started at a new job and can't go off on maternity straight away and risk my job" yadda yadda yadda.
When i was 15 years old i went onto the implant (this was not suitable for me to continue as it made me ill but due to age the doctors said i had to keep it in). The day my implant was finally removed shortly after my 18th Birthday i started with the depo shot and have been using this method since then up until 14/10/2016 (date of last shot).
I've had periods since coming off the injection the fist of which was 28/01/17 (lasted one week), then nothing until 27/05/17 (13 days), 23/07/17 (14 days), 15/08/17 (10 days) and nothing since. I'm now on day 62/63 if i've calculated correctly with nothing at all.
I've done several pregnancy tests (all negative) and have visited my GP who tested for infections etc that could cause this but nothing. I asked about a blood test and they said there was no point as i couldn't be pregnant.
I've had a lot of stress in the last 8 months or so with a lot of different matters and i know that won't be helping but I'm terrified that I've ruined my chances of becoming a mother.
I've also been taken off high dosage of Mirtazapine (antidepressant) due to it being unsafe to use while trying to conceive.
Sorry for ranting but has anyone had any similar issues with periods after the depo?