I grew in coco for admittedly too long before I really 'understood' that you are basically growing hydroponically like MickF is kindly suggesting. Totally drenched coco still provides a huge amount of oxygen to the roots so you don't have to worry about overwatering, it's more like every time you totally soak it you are putting your plant at its optimal state and the more often you can do it the better.
When he says flush, he means water it until 20%+ volume of your growing mediums worth of water has come out the bottom of your pot.
It's helpful to then TEST that runoff water on its own for its EC/TDS(ppm) and PH, mostly EC (as far as I know, I don't what useful info the PH might give you at the run-off stage unless it's totally whack, an indicator that something is off). If the EC is higher than what's going in, that means you have too many nutrients in your water, your plant can't handle it and it's building up in the coco. Likewise, if you're only watering every couple of days, that EC will drive up as the water evaporates and all that's left is the salt - also driving the nutrient dose up way too high for your young plant. On the flipside, if you can get things back to normal, you keep testing that runoff EC and if it's coming out lower than what goes in, this is your plant telling you it can handle a little bump up in nutrient intake, so you give it a little more next watering until you're getting roughly the same value on the runoff as you are going in.
At this stage your plant is looking a little rough but still alive. I'd follow Mick's advice and flush quite heavily for a start to bring her back to equilibrium, followed up with a solid daily watering schedule. You can start with no (though people suggest to never go pure water w/o any nutes in coco) so rather maybe very little nutes probably just to test the runoff to see how high the concentration is in there already. Flush until runoff concentration falls within a comfortable range, then start feeding light to normal and maintain the daily watering.
I've learnt that growing pure coco can be a joy with how well the plants respond to constant care, but it's definitely a little more tedious if you don't have a way of irrigating automatically.
