I find that it comes in waves.
DS is now 6 and I had a bit of a melt last year when I really needed time away from him as he was going through a bad patch with behaviour and I'd not been out for a looong time.
I used to find that evenings were the worst. I'd put him in bed and then feel trapped being in the house. With him being at school, I go out of the house every day and now have a job during school hours which is great.
I used to also get that single parent fever like cabin fever when I would get invited out to do things/go places and then not be able to because of childcare. At the moment, this isn't too bad as I've not spoken to those friends since around January when we had a bit of a tiff about a holiday abroad.
I find having other single parent friends does help a lot - and having some things organised to keep you sane that you can look forward to for the evenings and making sure that you have sometime during the course of the week where you are away from your daughter.
With regard to his tantrums etc, DD will get better with time, but SureStart are always a good place to get advice and help with anything - my local centre has been a godsend to me. Or ask your HV.
It will all get better with time, hang on in there. xx