Please help me, I hope I didn't do anything serious.

This is a brief rundown of my workout routine. For the past 6 months I have been working out for a multitude of reasons. I have all the weight machines I need right at home so I don’t currently have any need to join a gym. I also use dumbells besides the weight machines. Basically I do 3 sets of 8 repetitions for each of my workouts. I also do one set of 50 pushups and 2 sets of 60-70 pushups. I do this every other day and about once every 2 weeks or so I take a two day break. For the past 6 months this has been working pretty well for me although I am probably going to need to switch to a two day routine because I am planning on increasing the number of different exercises I do. I stretch regularly although not to the best of my ability and sometimes I slack off although the past month or so I got my ass in gear and started to try and stretch properly.

The problem is that last tueday I didn’t get out of work until late and didn’t get a chance to work out until 3 AM. I was rushing and wasn’t thinking about breathing properly or anything like that. The problem came when I was on my set of 60 pushups, I was rushing through them and I did about 23-25 pushups without taking a breath of air. I started to feel a tight pain in my neck and tried to fix it by breathing properly but around 37 pushups the pain became unbareble and I had to stop. The only way to describe it is by imagining somone removing your spinal cord and then taking all the nerves, blood vessels and what not and twisting them all together very tightly. No matter which position I put my neck in the pain would not subside and I tried laying down, sitting straight up and the only thing I could do was wait for it to stop and it took about a good 6 minutes to calm down. I then had a pretty good pain in my neck for the next 45 minutes or so and had a headache for the rest of the night. The next morning I also had a headache (although I don’t know if it was from sinesis or not) and the pain in my neck was still there.

On thurday I tried working out again and didn’t push myself to hard but the pain came back although not to the same degree as the last time. I tried again today this morning and the pain came back again but not to bad.

My question is this,
Do you know what I did to myself?
Are there any stretches I can do to prevent this in the future?
How long will this take to heal?
Is this really serious?
How bad did I screw up?

Thank you for your help and I am looking forward to seeing a response, it scared the crap out of me when it first happened and I would really like to identify the problem and fix it and prevent it form happening again. I’m done BSing around and from now on I’m going to take working out more seriously, especially since I’m moving into the heavier weights now.