Hi there just to try and reassure you (caveat ... All kids are different), we started on a Monday, she goes to nursery Mon-Thurs, and by the Friday she still hadn't been on the potty with me. I believe at nursery she sat on the potty a few times but also had lots of accidents. She would also wait until I put her nappy on after the bath to do a poo. I thought I'd never be able to go out again... I regretted starting the potty training. Then on the Friday, after doing a wee on both my sister, an hour or so later she then weed on me, but luckily i managed to transfer her to the potty mid wee... This was the first time she'd ever gone on the potty but I was able to make a song and dance about it, give her a reward etc. from then on it was relatively plain sailing. Poos took a few more days but essentially all in all, the day time potty training took about a week. Hideous for the first five days but then ok!
We did the potty training at 2 years and 4 months.
Based on my frame of reference I'd say keep at it... But good luck whatever you decide!
We're on Day 3 today and it suddenly got much better at about lunchtime, so maybe keep going for a bit if he's not getting too upset? Yesterday was terrible... But it suddenly seemed to start making sense to her and we had all but one wee in the potty from lunch (poos are another story, but I'm counting today as a success anyway ).