How do I get rid of the devil's whispers that suggest to me that not repeating the prayer, ablution, or purification is not doubt but laziness, especially since I am pregnant and cannot exert myself?

Satan seeks to corrupt worship and make life miserable through whisperings (waswasa). Therefore, one must ignore any doubts concerning the invalidation of ablution (wudu') or the corruption of prayer (salat), because Allah intends ease for His servants.