Hi Nicola,
I know...this is the hardest part...not knowing, exactly. I can "hear" it in your post. I'm so sorry you're having problems--as you can tell, you're not alone.
It was under my impression that you need a biopsy of one kind or another, before "lymphoma" can be fully diagnosed...although, I've seen on this forum something where they "watch & wait" to see if lymph nodes enlarge. That, I really don't know anything about, because once my node was biopsied, I've been in a whirlwind ever since! I'm just now settling into treatment and "accepting" this journey---I think after acceptance, THEN you start to get well. I've had many a person on here become my "cheerleader" & help me remain positive.
Maybe someone on this forum that has experienced the "watch & wait" syndrome can respond to you with more info.
Until then, think positively--because as I'm learning, lymphoma CAN be beat!

S.