How early can you catch on that you're pregnant? What are are signs and symptoms to look out for? Whats the earliest sign to notice?

4-5months na kasi my first trimester akala ko ay may gastric ulcer ako kasi suka talaga minu minuto for 3 months, diko nmn na sya morning sickness kasi grabe talaga naranasan ko. then nung 4-5 okay na ko pero napansin ko nmn lumalaki tyan ko, nagworry ako na baka may sakit ako sa bituka, nag PT at malabo yung isang line yung isa malinaw then ultrasound and confirmed 5 months pregnant