Hcg blood levels?

Side note, I have no dates to go off of because I havent had a period since fall.

3 days ago I took a FRER, faint positive

2 days ago i took a few frer and it was darker

Yesterday i took 3 frer and all were positive, faint but darker

Today I took a FRER and a Digital. Frer darker but not as dark as control line and "pregnant" on digital

OB drew blood this morning and result came back "22" which they said is considered pregnant and want to recheck Friday but I feel that is a really low number. Anyone else with a low number and have successful pregnancy. Weve been waiting 3 years and now I'm scared to death my levels are to low.