It could just be general stress. But there are many other explanations. I struggled with sleeping problems for many years and finally got it under control a few weeks ago. One of the things to check is your circadian rhytm. It is easily adjusted by getting enough sun in the day and keep lights off after sunset. Try not to eat too late. Eat the main part of your calories until afternoon. Try to do some light exercise. But do it early in the day. Try eating more protein. Sleeping time seems to correlate with protein consumption in most species. Don't be too busy after sunset. Don't do anything that engages your mind too much. And the most trivial of all: Have more sex. Or to be more precise, have more orgasms. That should knock you out pretty fast.
If everything fails, invest in some lab work. The most important things to check are thyroid, estrogen, progesteron, prolactin, serotonin, cortisol and adrenaline.