I’ve gotten up at 4:30am for years. It helps that I have two dogs who have established a routine with us, and so I set my alarm every day, even weekends, at 4:30 to get up for their first constitutional and half-breakfast. On work days I then sit for a half hour then get up and proceed with my toilette, breakfast, etc. On weekends I go back to bed and my husband gets up in a couple hours to give them their second half-breakfast and another constitutional.
I would recommend you write down the routine you used to follow. You know, what was your first activity upon waking, the order in which you took a shower/bath, got dressed, had breakfast, prepared for the day, departed the house, etc. Also write down the end of the day routines. How soon after arriving home did you have dinner, what TV programs did you watch or what evening activities did you engage in, if and when and how did you exercise, what routine did you follow in preparing for bed, etc.
Then apply approximate timelines. You took your shower/bath X number of minutes after arising, had breakfast X number of minutes later, departed the house X number of minutes later, and so on. Then adjust this schedule according to your new work hours. If you have a partner or housemate, share your results with them too, so they can help you adjust and stick to your routine. Tape your favorite programs so you can watch them at the usual time in your schedule. Download email to read offline. Et cetera, et cetera.
While I do not know for sure if this will solve your problem, it seems reasonable to me that it will go a long way towards helping you to adjust. We are all creatures of routine and rhythm. Carrying forward our routines to a new timeline makes more sense than just changing the alarm clock and hoping our bodies will somehow cope.