I know three sets of parents whose kids have taken their own lives. This thing is incredibly prevalent these days, and especially amongst young men.
I can't imagine what that must be like. It is every parents worst nightmare.
Grief can be very hard to cope with, but especially so in this sort of situation. Three months is so very very recent and it must take a long time to come to terms with this sort of thing. Have you thought about finding a specific grief peer support group? I think that might be extremely helpful. I had a quick look online and found 'compassionate friends' which is for grieving parents of children https://www.tcf.org.uk/ and bereavement uk also have a Facebook group for parents who have lost children. I am sure there will also be other groups in your local area as well.
I have some very good friends who lost their son at a similar age, in a similar way. If you wish i can ask them if they would talk to you about it. This happened five or six years ago now, so they are some way down the line.
One thing i would say though, is don't blame yourself Darren in any way, shape or form. Sometimes people make decisions and do things that we have very little control over, if any at all. The issue is that as parents we will naturally feel responsible for what our children do.
The poignancy of your post being made on fathers day was not lost on me. My heart goes out to you Darren and you and your family. I am sure that you will always find a sounding board on tz if you ever need to express anything.
Please take care of yourself mate and you can always ping me if you just need a pair of ears. best wishes. Dave