cheeky - I'm sure every single poster on this board has felt or feels some of what you have just said.
The first thing is really bollocks to being 'a good mum'. One persons definition of this is SO different to anothers. Really as long as you are doing the best YOU can, and your child is healthy and happy that is enough.
So, don't think you are not a good mum, honestly in your daughter's eyes you always will be and it really only matters what your child thinks - sod everyone else.
I think I read in one of your other threads that you don't feel that confident, well like anything this will build but you must take steps to build this. Really (I know they can get a little tiresome) but do join groups....
It take the pressure of YOU having to entertain as you are in a group situation.
It is 'support' even if you don't go for coffee or see the other mums again, you are being supported for that period.
What do you find stressful? Is it feeding, sleeping, play? All of the above can be changed to make life less stressful for you e.g - routines, online food shopping, hire a cleaner, do stuff with dd that you enjoy, so for e.g if you hate a soft play environment but love the park don't bother going to soft play. Your dd honestly won't give two hoots where she is as long as you are happy and she is with her mummy who is showering her with love and affection.
What about your partner? How much of a support is he? Be firm but fair, you are a team so try and do stuff as a family and stop all the lie ins at weekends -seriously, who needs a 4 hour lie in unless they are a teenager?
I find that if I am sick of dh or need space (we live in a small flat) I take ds out if he is in watching boring sport all day - why get under his feet or get pissed off with him that he is sat on his ass all day? Ds and I go out and do what I want to do, which normally involves, cake, coffee, library and walks - bliss...
However, when I walk in that evening with ds the tv will be turned off and HE will be doing bath and bed as I have been out for 6 plus hours allowing him 'his time'. Also, we take it in turns to go out with friends and I find just skulking into a cinema with a friend with popcorn and sweets for a couple of hours is wonderful - ds is asleep and dh happy to babysit and monopolise TV...
Implement this whatever works best for you - rota, discussion, instructing!
I would really make an appt with your GP and do some other research in terms of the support available, counselling etc, other networks where you live, you will be surprised what is available...
Good luck and sometimes life is a bitch, but also it is very much what you make it.....