For me, the single most important lesson I learned about sharpening chisels is the need to set the bevel angle in a reliable, consistent, repeatable way. If you cannot do that, the rest is moot. Clearly @lucid77
did not match the original bevel when he/she started grinding the new bevel angle onto the face of the chisel.
I had one of those commonplace, inexpensive honing guides with the small brass wheel and the large side screw that clamps the honing guide to the chisel. (I gave it away and replaced it with the Veritas set, see below.)
I made a jig out of scrap hard maple to set the honing angle, by setting the distance between the honing guide and the tip of the chisel. It didn't work reliably. The sharp chisel point would cut into the wood and not stop at a consistent place on the jig (yes, hard maple!). I set the honing guide using a combination square, but it was not ideal. The real solution is to make new bevels with the clamped chisel in one step, not releasing the clamp until the new bevel was completely ground into the face of the chisel. (For resharpening, I used the flat plate "matching" technique that I describe below.)
I think lucid77 should make a new bevel on the chisel. I would get a good extra course or extra extra course diamond stone, set the honing guide distance for a 25 degree bevel, and expect to spend a lot of time grinding that new bevel. First, make sure that the back of the chisel is flat. After that, set the honing guide, and make sure that it is tight and secure around the chisel and will not shift during the process. Keep the honing guide wheel flat on the stone and do not allow it to rock. Keep the diamond stone damp with water, and rinse it off frequently. You will see the new bevel edge work its way up the face of the chisel. For a 1/2 inch chisel, it can take 45 minutes to an hour. For a 3/4 inch chisel, it can take well over an hour. The wider the chisel, the more surface area on its face that you will have to remove. Be patient.
Once you have ground a good new bevel on your chisel, you don't want to lose it by adding lots of accidental micro-bevels, so the trick is to match the current bevel perfectly when you resharpen the chisel. Once you have ground the bevel on your chisel, which is something you won't want to do again, you will need to sharpen and resharpen it. Go through a set of increasingly finer grits of diamond stone or sandpaper until you achieve the sharpness you desire. For a final finish you can use Japanese water stones and/or leather stropping.
Flat Plate "Matching" Technique:
My trick for setting chisels for resharpening with the cheap traditional honing guide is to place the face of the chisel flat on a piece of glass or granite. Tighten the honing guide on the chisel, and then bring the wheel to the edge of the glass. With the chisel face flat on the glass, the wheel should barely touch ... "kiss" ... the surface of the glass as it reaches the edge of the glass. Adjust the honing guide if the wheel is above the surface or touches below the surface at the edge, until it is perfect. Tighten the honing guide so that it cannot come loose during sharpening, then recheck the setting. Is the bevel face perfectly flat on the glass? Does the wheel just kiss the glass? Is the chisel perfectly flat in the honing guide? Is the wheel perfectly perpendicular to the chisel blade?
Terry Q is right about the Veritas Mk. II Deluxe Honing Guide Set. I bought one and never looked back. I gave my traditional honing guide to a friend who asked if they could have it. The Veritas honing guide set is expensive, but oh so worth it if you are going to stay with flat stone (or sandpaper) grinding. The small metal "angle registration jig" enables repeatable placement of the nice, wide honing guide for any desired angle, including 25 degrees.
A shortcut would be to use a low speed grinding wheel, which has its own issues, including setting the bevel angle in an accurate, repeatable manner. I would not even consider trying a regular high speed grinder, which can so easily ruin the steel in my chisels. I have a Grizzly T10010ANV 10 inch wet grinder, which I use to sharpen round gouges, but still prefer to use flat stones for my chisels.
It takes patience to set a new bevel on a chisel, but it is a job that should only have to be done once, as long as you can set up your honing guide in a consistent, repeatable way.
If you have trouble setting up your honing guide consistently, then there is nothing wrong with using micro bevels. They cut equally well, and don't require such precision and patience. The problem with micro bevels is that eventually you will need to regrind a new bevel face on the chisel every once in a long while. It is a task I would prefer to avoid.
I hope this helps.