It happens. Do not panic, and do not double up.
What to do
Message your Care Team and ask. That is the real answer, because what to do depends on how late you are and where you are in your dose schedule.
What not to do
Do not take two doses to catch up. Do not take a late dose and then your regular dose close together. That is how people end up with severe nausea and vomiting.
Why the gap matters
Your body adjusts to these medications gradually. That is the whole point of stepping the dose up slowly. If too much time passes, that adjustment fades, and picking up at your previous dose can hit much harder than it did before. Your provider may bring you back at a lower dose and rebuild. That is normal, and it is not starting over.
As a rough guide, try to keep doses about a week apart, and treat a gap of more than about ten days as a reason to check in before you inject. Your own prescription instructions come first.
Making it easier to remember
Set a repeating alarm on your dose day. Keep the vial somewhere you will see it. Some people pair it with something they already do every week.