Be careful with positive affirmations
For people with low self-esteem, repeating 'I am lovable' made them feel worse.
Do this
If a self-statement feels false when you say it, do not repeat it harder. Use statements you can actually endorse, or drop the technique and work on behaviour and evidence instead.
Why it works
In a well-known experiment, participants with low self-esteem who repeated a positive self-statement reported worse mood than those who did not. The likely mechanism is that a statement far outside your range of believable views triggers counterargument, and you end up rehearsing the case against yourself.
Where it fails
This is one line of research with a small sample and mixed subsequent evidence. Self-affirmation of a different kind - reflecting on values that matter to you - has a substantially better track record and should not be confused with this.
How you’ll know
Say the statement and watch what your mind does next. If it immediately produces a rebuttal, you are strengthening the rebuttal.