You don't have to wait until you are at death's door to go to the doctor with a medical problem, and in exactly the same way, you don't have to wait until your mental health problems are really bad, before seeking counselling.
To continue the medical metaphor - going for counselling now is the equivalent of taking a short course of antibiotics for an infection, rather than waiting until the infection is far more serious and you need hospital admission and IV antibiotics.
It's also worth considering that low self esteem might be contributing to you believing you don't 'deserve' treatment/counselling/therapy - but that is a skewed view of reality, and in fact you absolutely DO deserve to get the help you need now.
I have had depression and low self esteem since my mid teens, and last year I had a course of Cognitive Behavioural Therapy, and I can honestly say it was amazing - it really helped me to recognise the self-sabotaging, unkind-to-myself thought patterns that have become so much of a habit, and it taught me ways to take back the control, and to handle my own symptoms.
If you don't know, CBT works on the theory that our thoughts, our actions and our emotions are three sides of the triangle, and each can influence the others - so having negative thoughts about yourself, for example, can make your mood lower/depressed - but the flip side is true too - by changing your thoughts, you can help raise your mood. Breathing exercises really helped me, as did visualisation. I can visualise the depression as a weight, filling my skull - and then I can imagine that weight lessening and lifting - and I feel a sense of relief. When my therapist taught me this, she suggested picturing the negative feelings/depression as a colour - a dark, unpleasant one - and then 'seeing' as the colour changes, at the edges at first, and then across the whole mass, until the dark, bad colour is driven out altogether by the lighter, happier colours. That didn't work for me, but as soon as I realised I 'saw' the depression as a weight not a colour, I got a handle on how to visualise it improving - if you see what I mean.
The bottom line - you are worth it. You deserve good mental health, and I would absolutely encourage you to go and get the help now.
Even if it is 'just' that work is stressful (and I put that in inverted commas, because stress can be really damaging) then I believe that bad stress, damaging stress isn't something you should have to put up with - and if some therapy helped you to manage your stress, so that you coped better with work, and by extension, with home life too - that would be a good thing.