Baby not sleeping as much

Amanda

My son is 12 weeks and for a couple weeks was sleeping through the night at least 7-8 hours at a time. Then, a few days ago he went back to only sleeping 3-4 hours and then waking up to eat. What is going on? Has this happened to anyone else and how long does it last? He is also harder to get to bed at night and has been crying a lot more during the day