Was the woman's first marriage contract valid, and was its annulment valid, and consequently, is the questioner's marriage to her valid and permissible for him, given the whispers (of doubt) he experiences?

If a man was forced into a marriage contract, the contract is invalid and has no effect. However, if he entered into it unwillingly (but not under duress), the contract is valid. If the contract was valid and a divorce occurred, whether initiated by himself, or through his father as an agent, or by a judge's ruling, or with the husband's consent, and then a new valid contract was made with her, she is his wife, and everything permissible for a man with his wife becomes permissible for him. One must be wary of yielding to obsessive thoughts (waswas) as their consequences are dire. The default assumption for contracts among Muslims is validity, and their invalidity is only ruled upon when a cause for invalidity is verified. It is recommended to seek Allah's help and supplicate frequently to be rid of obsessive thoughts.