Sore back at 5 weeks ?!

Hey ladies ! I am five weeks and 3 days and two days ago I started to get this dull lower right back pain (almost throbbing like) that lasted till yesterday night . Then this morning all seemed great. I went to my sons track and field got home and passed out because I was soooo tired, woke up and now my back on the right side feels sore. Has this happened to anyone else. This isn’t my first pregnancy. This is actually my fourth but I do not remember this with either of my boys. TIA🥰