Is a ghusl from seminal discharge sufficient for ritual bathing after masturbation, or does that require a separate intention? And is a ghusl from menstruation sufficient for ritual bathing after masturbation, or is that considered seeking out dispensations?

We ask Allah to grant you healing from whispers (waswas), and we advise you to disregard them. Ghusl (ritual bath) is not obligatory merely by masturbating unless it results in the emission of maniy (spermatic fluid). If maniy is emitted, ghusl is obligatory. The ghusl performed due to the emission of maniy suffices for the intention of purifying from masturbation. If you were unaware of the obligation of ghusl after the emission of maniy, there is a difference of opinion among scholars regarding making up the prayers you performed. The more cautious approach is to make them up. These prayers should be made up even if you are unaware of their exact number. As for ghusl from menstruation, it removes ritual impurity. If a menstruating woman is also in a state of janabah (major ritual impurity requiring ghusl), one ghusl with the intention of both purifications suffices, according to the majority of scholars. If she intended only one of them, there is a difference of opinion. Re-performing prayers is not prescribed unless their invalidity is certain, not merely due to doubt or whispers.