Previous ectopic pregnancy

So i had an ectopic pregnancy when i was probably 20. Thankfully we discovered it early and i only had to be given a shot.

I’m now 28 and today is Sunday the 15th. i found out i was pregnant on Friday night from a home pregnancy test because i missed my period. Yayyyy super excited till i remembered my last pregnancy was ectopic. Gyn told me to let them know next time i get pregnant so they can monitor me. Saturday i was able to find a walk-in gyn (thankfully) only to be told it’s still too early and won’t be able to see anything! Such a disappointment. My last period started on Feb 12th. She said at 4 weeks it’s impossible to see anything.

After how long should i wait???!! I want to know now if it’s ectopic or not. I was rushed to the hospital last time...