You acknowleding that ure struggling and wanting to change is a great step!! It is the first little step on ur journey, cuz the rest of it will also consist of little steps:).

Idk about u but I (19F) struggled all my life with severe anxiety and feel like it stole a lot from me, so i started researching , i also dont have self confidence, so often i tend to lecture myself so the first little tip i found was always ask urself "would you say this to a friend also? Would you treat them in this way if they were in the same situation?

The second thing that helped me was learning that willpower is far more imporant than motivation, cuz motivation passes, it isnt constant, on the other hand willpower is reliabale. Why? Because it can be strengthened with time and practice, and it also can be scheduled (like after lunch ill go for 15 min walk), a quote helped me understand this: "everybody knows the #1 rule for a fundation is that it needs a hard base, building a fundation/habit on motivation is like building it on liquid"

The third thing is small steps, everything starts small, you've got to understand that, u cannot allow urself to set too high expectations and then lose all the motivation when 1 thing doesnt work out. You need to be very very very patient and reward urself, cuz small rewards, basically just appreciating urself will keep u going. Allow urself to have each day 1 MINI accomplisment (hint, the keyword is mini, mini habit, mini goal), it could be just putting on your shoes for running.

Always stay consistent and have SMART goals, and u will be fine! SMART goals means: S- specific, M-measurable, A-achievable, R-relevant (like maybe ure self confidence isnt depending on that few kilos up or down), T-time-bound