I had a similar problem with my now almost 3 yr old son. He became a horrible napper once nursing was out of the picture. I weaned him around 21 months fully but from naps around 18 or 19 months because I was pregnant and it became too uncomfortable. When we started nap weaning it was really hard for about 3 weeks if I remember correctly. I think I blocked it out since I can't truly remember how long this lasted! It was so hard like you said because you get so run down. This is when he discovered he could jump out of the crib. So at first we put a twin mattress on the floor for him to sleep on then transitioned him to the toddler bed. Getting him in the toddler bed actually seemed to help because it was fun new bed and maybe he felt less trapped. We put child safety handles on his bedroom doorknobs tho so he couldn't get out of his room at night without us knowing.
For the first several months after nap weaning I resorted to stroller walks or car rides at naptime. He dropped the am nap and started napping just after lunch which helps because they're more tired by the time they get to nap. I eventually just started building a naptime routine. Letting him watch a short show that he likes to settle him down, bring to his room and read stories, turn on quiet relaxing baby einstein music, then I'd lay on the mattress by his bed and time for our nap! I'd either sleep too or sneak off after. Then I eventually started not laying down on the floor and just sat on the floor reading. Next it was leaving the door open and I'm in the hallway folding laundry or something. Now I go in the computer room next to his room and leave his door open til he falls asleep. He still to this day fights me on it sometimes when he really doesn't want to nap, but I know the more he complains when in bed, he's really tired and falls asleep shortly after the protesting.
I hope this helps. Feel free to email if you have any other questions that I might be able to help with. Best of luck and hang in there! It will get better with time - and if you're like me, after tears on both your parts! Take care.