I was out today fishing with the family and while heading home I hit a shallow area in the bay. I was running about 28mph and when we hit the shallow area we obviously slowed down and it pushed my outboard up as if I was trimming it up. The motor never shutoff and seemed to run fine during this whole process. Once clear of the shallow area the boat got back on plane just fine and ran home perfectly. When pulling into my marina I went to reverse into my slip but the motor would not shift into reverse. I tried multiple times and all it would do is rev up real high but no reverse. I could shift into forward and neutral with no issues. I tried doing a google search and have read anything from needing to replace the lower unit to it could just need a new hub inside the prop. I know I most likely need to have a mechanic check it out but was hoping someone on here may have some information for me as to what it could be. The motor is a 1993 Yamaha 150hp. I appreciate any help