Would like help with anxiety, stress, worry

Based on what you stated you're worried about, it sounds like some struggles that you deal with include managing your expectations, including worst-case scenarios, dealing with people, centering your emotions and taking in new data, which might be overwhelming to you.   In some ways, all of the items you mentioned seem like they have anxiety at the center of them.    

Negative feelings like this can be as intense as a waterfall, spiraling a person down emotionally, or more like a sink faucet being turned on.    Obviously, dealing with thoughts that come into the mind in the form of the sink faucet require less energy and can be handled with fewer mental resources.   With fewer negative thoughts coming in, one can also dissect them in a less urgent and more methodical manner.

Counselors often term frequent thoughts that enter the mind that lean toward a more worrisome point of view as Automatic Negative Thoughts.   They feel automatic because it seems to people as if they come regularly and seem to be triggered easily.   

One of the main strategies to disempowering the thinking is to recognize when a negative thought stream is provoked and to follow up with the provoked line of thinking with something countering the thought that has been provoked.  Let's say, for example, that the thought, "This person wasn't very friendly" is followed up by the further negative thinking pattern, "They must not like me."   The first thought comes from a perceived experience.    The second is a negative assumption based on the first: "They weren't friendly to me, so they must dislike me."  Of course, "They must dislike me" doesn't necessarily logically flow from "They weren't friendly."

Over time, correcting the unsound logic can help anxiety. It depends on the committed action of someone doing the mental work.   It usually involves the therapist challenging the thinking that contains negativity and encouraging the client to both keep working other anxious thoughts.   Working out best or realistic scenarios helps clients to combat the negative thinking.

At first, realistic or best-case scenarios may not come easily, but with practice, a client can gain speed and confidence and can fight overwhelming negative thinking patterns.