I haven't tested for most of my diabetic life. Don't really have a good explanation as to why I just haven't, I start testing, then stop at some point and don't realise for months on end. I've always taken my insulin though...well I say always, I can count on one hand the amount of times I've forgotten...however I'd have been as well not taking it as who knows what doses I was supposed to be taking as I wasn't testing.
I've had a running 'joke/quote' that I've been heard to say in that I'll need new kidneys before I'm 40...I now know that I will *NEED* a new kidney before I'm 30...given I'll be 30 at the end of this year that's a very very scary thought.
Without giving a lecture, you NEED to test, and seek help about not testing now before you end up like me. I've recently started testing again, part of the reason for that was changing meters and the features of the app attached to the meter send me reminders to test which I've never taken advantage of before - it's not solely down to the the meter and I'm sure the functions it has are available through other meters but this one has turned my attitudes around so it has helped, it's just too late in my case for any changes I make to stop the complications from happening - but you sound like you have the chance to stop something, and signing up and asking for advice/discussing it on here is a great first step

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You say you feel 'slightly' depressed, I'm going to go out on a limb and say anyone with diabetes, t1 especially is at risk of being depressed, in fact anyone with any chronic medical condition is - the trick with depression is seeking the help and advice with it before it causes problems. NOT seeking help/advice in relation to my depression has cost me relationships, my health and potentially a long & bright future.
Don't end up where I am whilst you have the option to not to is all I would say - you've taken a great first step in coming here, so take the next steps by following some of the advice you've been given as well =) All the best =)