I think when my kids were younger, I was frequently overwhelmed and emotionally distant, how do I make it up to them?

[OwlBeGone]

I've come to this realisation gradually, or rather admitted it to myself after long repressing it. They're 16 and 19 now. I have found motherhood very hard and came from a very dysfunctional family. I think I've got a lot wrong over the years. I was often irritated and overwhelmed by the kids when they were small. I've had mh issues over the years (mainly depression on and off since a teenager) None of this is meant to be excuses, though it probably sounds like it.

I don't think I was/am a really bad mother but emotionally distant at times which is bad in itself. I feel like I want to apologise to my daughter in particular but maybe that's just about making myself feel better? She's never said anything specific about the way she was brought up but she has her own struggles and isn't good about talking about problems. I don't even know what I'm asking here. Would therapy be a good option, to talk through my feelings instead of burdening my children with them? I feel like I might have damaged them.

Please get therapy first. Make sure you can regulate your own emotions. Make sure that you're ready to shoulder whatever your children have to say about you and your motherhood and the impact it's had on them. If you talk to them, make sure it's about them and their needs, rather than their own.
There's a difference between appologising because you'll feel better getting it off your chest, or listening to what your children have to say, validating their emotions, taking responsability and appologising for the part you played in their emotional health.

Your children don't need the added burden of worrying about you, handling your guilt, reassuring you that they are okay, and setting their own feelings aside because they worry you can't handle to hear what they have to say.

Thanks, good advice.

Agree with PP.
Also, when you say your daughter is not good at talking about her problems.

Kindly, if you have been emotionally distant she won't have been able to share her problems with you.

It wouldn't have occurred to me as a teenager that my mother was someone who wanted to hear my problems, someone I wanted to tell them to , someone who could help

We all get this guilts, OP. I carry plenty of it. I look back to when I haven't reacted in the best way to some of the things my children did.
I just wanted to offer you a hug.

OP, therapy could be a good thing, including in developing compassion for yourself and a recognition of how context and your own childhood will have influenced the choices available to you. There are no perfect parents. I am sure you did your best under what sound like difficult circumstances.