Oh that sounds tough! How long has he been in nursery?
We are having similar difficulties with nursery settling, so some good news stories would be helpful.
For my part, we are eventually, slowly getting there - after 2 months!- my DS finally had a couple of days last week where there were no tears all day (except at drop off) and he was waving bye to his keyworker at the end of the day.
For the not eating - DS also only eats minimally from the nursery food. However he will generally eat food from home. The nursery staff are happy to give him those, provided we supply an ingredients list, so he's been going in with a lunch box. The room lead said that eating is something he has control over, so when he's feeling more comfortable in the new environment she thinks he will be happier with eating their food.
Is your son eating at home? If not, it might be something like teething or illness that is making him not want to eat.
For the distress and early pickups: how many days a week is he going and are they consecutive? The more days they go, the faster they adjust to the "new normal" apparently. We've switched our days around so that he can go 4 days together rather than a day off in the middle of the week, which hopefully helps a bit!
At the beginning, we did a lot of part days and short days so that he gradually built up the time there. Do you or your partner have the option to use some leave and work half days for a bit so that your son can get more settled in nursery without having to spend more time there than he can tolerate?
I also leaned in to providing a lot of comfort and support at home. We've gone back to feeding to sleep and some co-sleeping (without a bad effect on overall number of wake-ups!), and I think this has helped him to feel more secure despite long days at nursery.
I would also look at whether you are seeing any progress towards settling at nursery. It has taken us 2 months to get to a reasonably happy baby at nursery, but along the way we could see smaller steps - the nursery staff reporting that he was able to sleep without being held and that he was playing more for example, and I also saw him feeling more comfortable and confident with my family when they visited last month. Without those small steps, I might have pulled him out and found another childcare option, but because we were seeing gradual progress I have been more willing to keep trying.