Many hugs sweetie, I tried to exclusively pump when BF didn't work out for us. I managed for 6 weeks before I couldn't keep going with it, you are doing so incredibly well to keep that going. I do understand what you mean about the lack of napping getting to you, particularly with the added pressure of needing to pump.
It sounds like you are describing OT naps of 30 mins, which could be a sign that your LO is not coping well with he long days. Sorry if i wasn't clear in what i was suggesting.If your LO is waking up between 5.30 & 6am, you would want to go for a BT 12 hours approx after that - I.e. 6pm. I went through this myself while I was trying to stretch out the A times when DD was small. It seems terrifying at the time - I was imagining 3am wake and start to the day, but it was never that bad. Going with the shorter day meant that DD slept for a longer night & caught up some of that OT. Later on (a few weeks later) she had started regularly sleeping longer nights and as I extended her first A time the morning starts moved later too.
My advice (& like jessmum has said it is just advice not the only way) would be to start a new day with a slightly longer A time before the first nap. You may get OT 30 min naps for a few more days while the lengthening process takes effect but when she hits a good A time & when the nights are longer for her it will settle down.