Must I fast the day I suspect I broke my fast on during the last Ramadan before the current Ramadan begins, knowing that the intention for the fast was made during the day and not at night?

If you are not certain that you broke your fast, then nothing is required of you, because the original state is the acquittal of responsibility. However, if you are certain that your fast was broken by masturbation that resulted in the emission of semen, or if semen was emitted due to repeated looking, then you must make up for that day. Fasting with an intention made during the day is not sufficient; rather, the intention must be made the night before. In addition to making up the fast, you are required to pay an expiation (fidya) of feeding a poor person, unless you were unaware of the prohibition of delaying the make-up fast.