Perhaps you need to spend a few quiet days getting your thoughts together. Think about what you really want to do: give life another chance, or ctb. There is no rush. Beachy Head isn't going to go away.
It seems to me that jumping is one of the more difficult things to do. Survival instinct will kick in for most people. (Even though I did a lot of mountaineering when I was younger, I still feel distinctly uneasy if I'm at the top of a vertical drop, without any protection.) If you are determined to ctb that way, then perhaps you should go through it carefully in your mind, beforehand. Think what it will be like looking down. Then ask yourself if you would be able to jump. If the answer is "No" or "I'm not sure" then probably you should look for another method.
There are other high cliffs along the south coast of England, if you want somewhere a little quieter than Beachy Head.
If you choose a bridge, note that to be almost certain of dying you need a drop of 100 feet or more, and a landing on a hard surface, such as concrete or rocks. Not many bridges in southern England meet those criteria. You may die from less than 100 feet, but the smaller the drop the greater the chance of surviving - probably with very serious injuries.
If you do decide to ctb, and want your posts deleted, talk to one of the moderators.
Whatever you decide, we are here for you.
Good luck.