after plenty of time I made a flight with the 737 again. Right after take off the trim was constantly adjusting automatically which then after around 10 minutes of flying caused it to be at 15. While being in autopilot with no climb rate the plane was pitching up so much that my speed dropped from 280 to 130 and I was going down while having the nose up way too much. When disconnecting autopilot I was able to put the trim down slowly, but everytime I put in the autopilot it started again. It did not even try to pull down. Is this normal? It does not seem like its normal.