My son used to go four days a week. He ran in happily and sometimes asked to go at the weekend, so it can't have been that bad! (He liked nursery a lot better than he does school.) If you're confident it's an excellent nursery and he's happy to go in, it's fine.
I didn't particularly enjoy toddlerhood either. It's relentless and exhausting. I used to get through my day with him by having a plan and going out somewhere different each week - places I liked, as he was happy with something different to look at and a run around on some grass or in the library. I'd usually drive into town first thing, wander round some shops with him in the pushchair, take him to the library, get a nice lunch from M&S and have a picnic in the park or go to Costa if the weather was bad (they seem to be quite good with kids) and then drive home at naptime so he'd drop off quickly. Transfer to cot one home or let him sleep in my arms if he woke up a bit. Then after he woke up we'd go for a walk around the block or just watch TV while I cooked dinner or did housework.
That was my basic day, but I had list on my phone of other things to do. Local gardens, museum, sculpture park, farm, visit grandparents or friends if they were off work.
I promise it gets better. I found a big difference around 2.5, and then again at 3.5. He's now 5 and although he's still quite hard work sometimes, he's brilliant and I love spending time with him. I don't dread it like I did when he was 18 months.
Can you take some annual leave as well? A week off with him in nursery for most of it might help.